Week to Second Converter
Convert weeks to seconds with our free online time converter.
Quick Answer
1 Week = 604800 seconds
Formula: Week × conversion factor = Second
Use the calculator below for instant, accurate conversions.
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All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.
Week to Second Calculator
How to Use the Week to Second Calculator:
- Enter the value you want to convert in the 'From' field (Week).
- The converted value in Second will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Time category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Week to Second: Step-by-Step Guide
Converting Week to Second involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Week = 6.0480e+5 secondsExample Calculation:
Convert 60 weeks: 60 × 6.0480e+5 = 3.6288e+7 seconds
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
Need to convert to other time units?
View all Time conversions →What is a Week and a Second?
The week (symbol: wk or w) is a unit of time equal to 7 days, 168 hours, or 10,080 minutes.
Official status: The week is not an SI unit, but it is accepted for use with the SI due to its universal cultural importance. The SI base unit of time is the second, and the day is the fundamental accepted non-SI unit.
Standard conversions:
- 1 week = 7 days (exact)
- 1 week = 168 hours (7 × 24)
- 1 week = 10,080 minutes (7 × 24 × 60)
- 1 week = 604,800 seconds (7 × 24 × 60 × 60)
- 1 year ≈ 52.14 weeks (365 ÷ 7)
- 1 month ≈ 4.35 weeks (30 ÷ 7)
The 7-day structure: The week consists of seven consecutive days, typically organized as:
International (Monday-first) convention:
- Monday (Moon's day) - Start of work week
- Tuesday (Tiw's day, Norse god of war)
- Wednesday (Woden's day, Odin)
- Thursday (Thor's day, god of thunder)
- Friday (Frigg's day, goddess of love)
- Saturday (Saturn's day)
- Sunday (Sun's day) - Traditional day of rest
US (Sunday-first) convention:
- Sunday considered first day of the week on US calendars
- Work week runs Monday-Friday
- Weekend is Saturday-Sunday
ISO 8601 standard:
- Monday is officially day 1 of the week
- Sunday is day 7
- Week numbering: Week 1 contains first Thursday of year
Workweek vs. weekend:
- Workweek/weekdays: Monday-Friday (5 days) in Western tradition
- Weekend: Saturday-Sunday (2 days) in Western tradition
- Varies by culture: Friday-Saturday in Muslim countries, Sunday only historically
Why 7 days, not 5, 8, or 10? Unlike the day (Earth rotation) or year (orbital period), the week has no astronomical basis. It's purely a human cultural construct that gained universal adoption through:
- Ancient Babylonian astronomy (7 visible celestial bodies)
- Jewish religious tradition (Genesis creation, Sabbath commandment)
- Christian adoption and spread (Sunday worship)
- Islamic adoption (Friday as holy day)
- Roman Empire standardization (321 CE Constantine decree)
- Deep cultural entrenchment making change impractical
What Is a Second?
The second (symbol: s) is the SI base unit of time, defined with extraordinary precision using atomic physics rather than astronomical observations.
Official SI definition (since 1967): The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom at absolute zero temperature and at rest.
In simpler terms:
- Caesium-133 atoms oscillate at a precise frequency when energized
- One second equals exactly 9,192,631,770 of these oscillations
- This provides a natural, unchanging standard independent of Earth's rotation
Why this matters: This atomic definition provides accuracy to better than 1 second in 100 million years for modern atomic clocks, enabling:
- GPS navigation (accuracy requires nanosecond precision)
- Global telecommunications synchronization
- Scientific experiments requiring extreme precision
- Financial transaction timestamps
- Internet infrastructure coordination
Second vs. Other Time Units
Subdivisions of the second:
- 1 decisecond (ds) = 0.1 s = 10⁻¹ s (rarely used)
- 1 centisecond (cs) = 0.01 s = 10⁻² s (stopwatch hundredths)
- 1 millisecond (ms) = 0.001 s = 10⁻³ s (computer operations)
- 1 microsecond (μs) = 0.000001 s = 10⁻⁶ s (electronics, photography)
- 1 nanosecond (ns) = 0.000000001 s = 10⁻⁹ s (computer processors, GPS)
- 1 picosecond (ps) = 10⁻¹² s (laser physics, molecular vibrations)
- 1 femtosecond (fs) = 10⁻¹⁵ s (ultrafast lasers, chemical reactions)
Multiples of the second:
- 60 seconds = 1 minute
- 3,600 seconds = 1 hour
- 86,400 seconds = 1 day
- 604,800 seconds = 1 week
- 31,536,000 seconds = 1 year (365 days)
- 31,557,600 seconds = 1 Julian year (365.25 days)
Note: The Week is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Second belongs to the imperial/US customary system.
History of the Week and Second
of the Week
Ancient Babylonian Origins (c. 2000-1000 BCE)
The 7-day week's roots lie in ancient Mesopotamian astronomy and astrology:
Babylonian astronomy:
-
Observed seven "wandering stars" (planets) visible to naked eye:
- Sun (Shamash) - brightest object
- Moon (Sin) - most obviously changing
- Mercury (Nabu) - messenger god
- Venus (Ishtar) - morning/evening star
- Mars (Nergal) - red planet, war god
- Jupiter (Marduk) - king of gods
- Saturn (Ninurta) - slow-moving
-
Each celestial body "ruled" one day
-
Seven was considered mystical/sacred number
-
Used in astrological predictions and religious rituals
Why 7 was special:
- Seven visible "planets" (including Sun and Moon)
- Seven days between moon phases (~7.4 days per quarter)
- Mathematical: 7 is prime, making it special
- Religious significance in Near Eastern cultures
Note: The moon's phases (29.5 days ÷ 4 ≈ 7.4 days) may have influenced the 7-day cycle, though it doesn't align perfectly.
Jewish Religious Codification (c. 1500-500 BCE)
The Hebrew Bible (Torah) embedded the 7-day week in religious law:
Genesis creation narrative (Genesis 1:1-2:3):
- Day 1: Light and darkness
- Day 2: Sky and waters
- Day 3: Land, seas, plants
- Day 4: Sun, moon, stars
- Day 5: Fish and birds
- Day 6: Land animals and humans
- Day 7: God rested → Sabbath (Shabbat)
Fourth Commandment (Exodus 20:8-11):
"Remember the Sabbath day, to keep it holy. Six days you shall labor and do all your work, but the seventh day is a Sabbath to the Lord your God."
Sabbath observance:
- Saturday (7th day) as mandatory day of rest
- No work permitted (cooking, travel, commerce)
- Synagogue worship and family meals
- Violations carried severe penalties (death in ancient times)
- Core to Jewish identity for 3,000+ years
Jewish week structure:
- Days numbered: Yom Rishon (Day 1) through Yom Shishi (Day 6)
- Only Shabbat (Sabbath, Day 7) has a name
- Week begins Saturday evening (sunset) and ends following Saturday sunset
Greek and Roman Adoption (300 BCE - 400 CE)
Greek influence:
- Hellenistic astronomers (post-Alexander) adopted Babylonian astrology
- Each day associated with a planet/deity
- Week spread through Greek-speaking world
- Ptolemy's astrology (2nd century CE) codified planetary hours and days
Roman nundinal cycle (753 BCE - 321 CE):
- Romans initially used 8-day market week (nundinae)
- Days labeled A through H
- Markets held every 8th day
- Used for agricultural and commercial scheduling
Planetary week adoption (1st-3rd century CE):
- 7-day planetary week entered Rome from Near East
- Coexisted with 8-day nundinal cycle
- Gradually replaced nundinal week for religious/astrological reasons
- Days named after planets/gods:
- Dies Solis (Sun) → Sunday
- Dies Lunae (Moon) → Monday
- Dies Martis (Mars) → Tuesday (Tiw = Germanic Mars)
- Dies Mercurii (Mercury) → Wednesday (Woden = Germanic Mercury)
- Dies Jovis (Jupiter) → Thursday (Thor = Germanic Jupiter)
- Dies Veneris (Venus) → Friday (Frigg = Germanic Venus)
- Dies Saturni (Saturn) → Saturday
Constantine's decree (321 CE):
- Emperor Constantine I officially recognized the 7-day week
- Declared Sunday (Dies Solis) a day of rest
- Aligned with Christian practice (resurrection day)
- Marked official end of nundinal cycle
- Made 7-day week legal standard across Roman Empire
Christian Transformation (1st-5th century CE)
Early Christian practice:
- Jewish Christians initially observed Saturday Sabbath
- Gradually shifted to Sunday (Dies Dominica, "Lord's Day")
- Commemorated Jesus's resurrection (Sunday morning)
- Sunday worship established by 100 CE
Christian week structure:
- Sunday: Lord's Day, primary worship
- Monday-Saturday: Workdays
- No Sabbath work prohibition (unlike Judaism)
- Sunday rest became custom, not religious law initially
Church influence:
- Constantine's decree (321 CE) made Sunday official rest day
- Christian terminology replaced pagan planet names in some languages:
- Portuguese: Domingo (Sunday = Lord's Day), Segunda-feira (Monday = Second day)
- Some Slavic languages: similar pattern
- Christian calendar organized around Sunday as "first day of week" (Western tradition)
Medieval Christian week:
- Elaborate liturgical calendar
- Different saints' days on specific weekdays
- Friday fasting (commemorating crucifixion)
- Sunday mandatory Mass attendance
- Week structured around religious observances
Islamic Adoption (7th century CE)
Islamic week (al-usbūʿ):
- Adopted existing 7-day week structure
- Friday (Jumu'ah) designated as day of congregational prayer
- Not a "day of rest" like Sabbath/Sunday—work permitted
- Friday midday prayer (Jumu'ah prayer) mandatory for men
Islamic day names:
- Days numbered similar to Hebrew tradition
- Saturday: Yawm as-Sabt (Day of the Sabbath—Hebrew influence)
- Sunday: Yawm al-Ahad (First day)
- Monday: Yawm al-Ithnayn (Second day)
- ...
- Friday: Yawm al-Jumu'ah (Day of Congregation)
Spread of Islamic week:
- Islamic expansion (7th-15th centuries) spread 7-day week to:
- North Africa
- Middle East
- Central Asia
- Parts of Southeast Asia
- Reinforced 7-day week as global standard
Global Standardization (1500-1900)
European colonialism:
- Spanish, Portuguese, French, British empires spread 7-day week
- Christian Sunday observance imposed in colonies
- Replaced indigenous time-keeping systems:
- Aztec 13-day and 20-day cycles
- Mayan complex calendar system
- Various Asian lunar-based systems
East Asia adoption:
- China: Adopted 7-day week in early 20th century (previously used 10-day xún divisions)
- Japan: Officially adopted 7-day week in 1873 during Meiji Restoration
- Korea: Adopted with modernization in late 19th/early 20th century
International commerce:
- Global trade required synchronized schedules
- Shipping and maritime schedules used 7-day week
- Telegraph and later telecommunications standardized weekly communications
Failed Reform Attempts
Despite universal adoption, several attempts to "improve" the week failed:
1. French Revolutionary Calendar (1793-1805):
- Replaced 7-day week with 10-day décade
- Aligned with metric system (10 days per week, 3 weeks per month)
- Days numbered Primidi through Décadi
- Only Décadi was rest day (1 in 10 vs. 1 in 7)
- Failed because:
- Less frequent rest days unpopular with workers
- Conflicted with Christian Sunday observance
- Disrupted social and family patterns
- Napoleon abolished it in 1805
2. Soviet 5-day and 6-day weeks (1929-1940):
-
1929-1931: 5-day "continuous week"
- Days numbered 1-5
- Each worker got one of five days off (rotating)
- Goal: Continuous factory production
- Problem: Families/friends couldn't synchronize time off
-
1931-1940: 6-day week
- Days numbered 1-6
- Day 6 was universal rest day
- Goal: Improve on 5-day system
- Problem: Still disrupted religious observance, traditional patterns
-
1940: Return to 7-day week
- Abandoned experiments
- Restored traditional Sunday rest
- 7-day week too culturally embedded to change
3. International Fixed Calendar (1923-present, never adopted):
- Proposed by Moses B. Cotsworth
- 13 months of 28 days each (4 perfect weeks per month)
- Extra month called "Sol" between June and July
- One "Year Day" outside the weekly cycle
- Never adopted because:
- Would disrupt all existing calendars
- Breaking the continuous 7-day cycle unacceptable religiously
- Massive economic costs
- Resistance from established institutions
4. Other proposals:
- Decimal weeks (10 days)
- 5-day weeks (aligned with work week)
- 8-day weeks (better divides into month)
- All failed: Cultural inertia too strong
Modern Universal Adoption
Current status:
- All 195+ countries use the 7-day week
- Synchronized globally despite cultural differences
- ISO 8601 standard (Monday = day 1, week 1 contains first Thursday)
- Different weekend patterns:
- Saturday-Sunday: Most of world (Christian tradition)
- Friday-Saturday: Many Muslim countries (Saudi Arabia, UAE until 2022)
- Friday only: Iran
- Sunday only: Historical in some countries
Why 7-day week succeeded:
- Religious universality: Judaism, Christianity, Islam all use 7-day week
- Ancient origins: 3,000+ years of continuity
- Global colonization: European powers spread it worldwide
- Economic integration: International commerce requires synchronization
- Cultural entrenchment: Too deeply embedded to change
- Mathematical convenience: Fits reasonably with months (4-5 weeks)
- Work-rest balance: 5-2 or 6-1 work-rest ratio culturally accepted
Modern cultural significance:
- Phrase "work week" universal
- "Weekend" concept global (even if different days)
- Weekly planning horizon standard
- Pay periods often weekly or bi-weekly
- Television programming on weekly schedules
- Religious observances every 7 days
- Social rhythms organized weekly
Ancient Origins: Babylonian Mathematics (3000 BCE)
The division of time into units of 60 has roots in ancient Babylonian sexagesimal (base-60) mathematics:
Why base-60?
- Highly divisible: 60 has divisors 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
- Finger counting: Babylonians counted 12 finger segments (phalanges) on one hand using the thumb, repeated 5 times for the other hand (12 × 5 = 60)
- Astronomical convenience: 360 days approximated the year (6 × 60), aligning with the 360-degree circle
Time divisions established:
- 1 day = 24 hours (2 × 12)
- 1 hour = 60 minutes
- 1 minute = 60 seconds
This system spread through ancient Egypt, Greece, and Rome, persisting for over 4,000 years.
Medieval Development: Mechanical Clocks (1200s-1600s)
The word "second" derives from Medieval Latin "pars minuta secunda" meaning "second minute part" (the second division of the hour):
- First division: Hour divided into 60 "pars minuta prima" (first minute parts) = minutes
- Second division: Minute divided into 60 "pars minuta secunda" (second minute parts) = seconds
Early mechanical clocks (1200s-1300s):
- Displayed only hours, no minute or second hands
- Too imprecise to measure seconds accurately
- Driven by falling weights and escapement mechanisms
Pendulum revolution (1656):
- Christiaan Huygens invented the pendulum clock
- First clocks accurate enough to measure seconds reliably
- Pendulum period provided regular "tick" for second counting
- Accuracy improved from 15 minutes/day to 15 seconds/day
Marine chronometers (1700s):
- John Harrison developed precise clocks for navigation (1730s-1760s)
- Accurate timekeeping enabled longitude determination at sea
- Precision to within 1 second per day
Astronomical Definition: Mean Solar Second (1832-1967)
In 1832, the second was formally defined as 1/86,400 of a mean solar day:
- Mean solar day: Average length of a solar day over a year (accounts for Earth's elliptical orbit)
- 86,400 seconds: 24 hours × 60 minutes × 60 seconds
Problems with astronomical definition:
- Earth's rotation is irregular: Tidal friction gradually slows rotation (~2 milliseconds per century)
- Seasonal variations: Earth's orbit affects day length by milliseconds
- Unpredictable fluctuations: Earthquakes, atmospheric changes affect rotation
- Increasing demand for precision: Radio, telecommunications, science required better accuracy
By the 1950s, astronomical observations showed the "second" was not constant—the length varied by parts per million depending on the era.
Atomic Revolution: Caesium Standard (1955-1967)
1955 - First caesium atomic clock:
- Louis Essen and Jack Parry at UK's National Physical Laboratory built the first caesium atomic clock
- Demonstrated caesium-133 atoms oscillate at precisely 9,192,631,770 Hz
- Accuracy: 1 second in 300 years (far exceeding astronomical clocks)
1967 - Official redefinition: The 13th General Conference on Weights and Measures (CGPM) redefined the second:
"The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom."
Why caesium-133?
- Atomic property: Transition frequency is a fundamental constant of nature
- Highly stable: Unaffected by temperature, pressure, or electromagnetic fields
- Reproducible: Any caesium-133 atom behaves identically
- Practical: Relatively easy to construct atomic clocks using caesium
Impact:
- Timekeeping became independent of Earth's rotation
- Precision improved from parts per million to parts per trillion
- Enabled GPS, internet synchronization, telecommunications, and modern science
Modern Atomic Clocks (1990s-Present)
Caesium fountain clocks (1990s):
- Atoms launched upward in "fountain" configuration
- Gravity slows atoms, allowing longer measurement time
- Accuracy: 1 second in 100 million years
Optical lattice clocks (2000s-2020s):
- Use strontium or ytterbium atoms instead of caesium
- Operate at optical frequencies (100,000× higher than caesium)
- Accuracy: 1 second in 15 billion years (age of the universe!)
- May redefine the second in future decades
Applications requiring atomic precision:
- GPS satellites: Nanosecond errors cause position errors of ~1 foot
- High-frequency trading: Microsecond timestamps for financial transactions
- Telecommunications: Synchronizing cell towers and internet infrastructure
- Science: Detecting gravitational waves, testing relativity, fundamental physics
Leap Seconds: Reconciling Atomic and Astronomical Time
The problem:
- Atomic time (TAI): Runs at constant rate based on caesium clocks
- Earth rotation (UT1): Slows gradually due to tidal friction
- Difference: ~2 milliseconds per day (accumulates ~1 second every 18 months)
Solution: Leap seconds (since 1972):
- Coordinated Universal Time (UTC) = atomic time adjusted to stay within 0.9 seconds of Earth rotation
- Leap second: Extra second added (or removed) on June 30 or December 31
- 27 leap seconds added between 1972-2016 (none since 2016)
Controversy:
- Leap seconds cause problems for computer systems, GPS, networks
- Debate ongoing about abolishing leap seconds in favor of pure atomic time
- Possible change may occur in the 2030s
Common Uses and Applications: weeks vs seconds
Explore the typical applications for both Week (imperial/US) and Second (imperial/US) to understand their common contexts.
Common Uses for weeks
When to Use seconds
The second is the universal foundation for all time measurement in modern civilization:
1. Timekeeping and Clocks
Everyday timekeeping:
- Wristwatches and clocks display hours, minutes, seconds
- Smartphones synchronize to atomic time via network
- Wall clocks, alarm clocks, digital displays
- Public time displays (train stations, airports, town squares)
Precision timekeeping:
- Atomic clocks: Caesium, rubidium, hydrogen maser clocks
- GPS satellites: Carry atomic clocks for navigation
- Scientific facilities: National metrology institutes maintain primary time standards
- Network Time Protocol (NTP): Synchronizes computer clocks to microsecond accuracy
2. Scientific Research and Experiments
Physics experiments:
- Measuring particle lifetimes (nanoseconds to picoseconds)
- Timing light pulses in lasers (femtoseconds)
- Gravitational wave detection (millisecond timing precision)
- Quantum mechanics experiments (Planck time: 10⁻⁴⁴ seconds)
Chemistry:
- Reaction kinetics and rates
- Spectroscopy (measuring light absorption/emission frequencies)
- Femtochemistry (bond breaking/forming at femtosecond scale)
Biology:
- Neural signal timing (milliseconds)
- Cellular processes (seconds to hours)
- Ecological cycles (days, seasons, years measured in seconds)
3. Computing and Digital Systems
Processor operations:
- CPU clock speeds measured in GHz (billions of cycles/second)
- Instruction execution times (nanoseconds)
- Cache latency, memory access times
Software and programming:
- Timestamps (Unix time: seconds since January 1, 1970)
- Timeouts and delays
- Animation frame rates (60 frames/second = 0.0167 s/frame)
- Video frame rates (24, 30, 60 FPS)
Database and logging:
- Transaction timestamps (millisecond or microsecond precision)
- System logs with second-level granularity
- Performance monitoring (operations/second)
4. Telecommunications and Networking
Network synchronization:
- Cell towers synchronized to GPS time (nanosecond precision)
- Internet infrastructure timing
- 5G networks require nanosecond coordination
- Precision Time Protocol (PTP) for industrial networks
Data transmission:
- Bit rates measured in bits/second (Mbps, Gbps)
- Latency measured in milliseconds
- Packet timing and queuing
5. Navigation and GPS
Global Positioning System:
- Atomic clocks on satellites (accuracy ~10 nanoseconds)
- Signal travel time calculations
- Position accuracy requires nanosecond precision
- GNSS systems (GPS, GLONASS, Galileo, BeiDou)
Aviation:
- Aircraft navigation timing
- Air traffic control coordination
- Flight duration measurements
6. Financial and Trading
High-frequency trading:
- Microsecond timestamps on transactions
- Trading algorithms execute in microseconds
- Market data feeds timestamped to nanoseconds
- Regulatory requirements for precise time-stamping
Banking:
- Transaction timestamps
- Interest calculations (per second for some instruments)
- Automated trading systems
7. Sports and Athletics
Competition timing:
- Track and field (0.01 second precision)
- Swimming (0.01 second precision)
- Skiing, bobsled (0.01 second precision)
- Motor racing (0.001 second precision)
Training and performance:
- Stopwatches for interval training
- Heart rate monitors (beats/second)
- Pace calculations (minutes per kilometer/mile)
- Reaction time testing
8. Manufacturing and Industrial
Process control:
- Machine cycle times (seconds)
- Assembly line timing
- Quality control measurements
- Synchronization of robots and automation
Industrial timing:
- Conveyor belt speeds
- Injection molding cycle times (2-60 seconds typical)
- 3D printing layer times
- Chemical process durations
Additional Unit Information
About Week (wk)
How many days are in a week?
Exactly 7 days in every week, universally across all cultures and countries worldwide.
This has been standard for over 2,000 years, originating from:
- Ancient Babylonian astronomy (7 visible celestial bodies)
- Jewish religious tradition (Genesis 7-day creation + Sabbath)
- Roman adoption and global spread
The 7-day week has no astronomical basis (unlike day or year) but achieved universal cultural adoption.
How many hours are in a week?
Exactly 168 hours in one week.
Calculation: 7 days × 24 hours/day = 168 hours
Context:
- Work week: 40 hours (standard full-time) out of 168 total
- Sleep: 56 hours per week (8 hours/night × 7 nights)
- Leisure: 168 - 40 (work) - 56 (sleep) = 72 hours
- Work-life balance: Only ~24% of week spent working (40/168)
Why does a week have 7 days?
The 7-day week has cultural and religious origins, not astronomical:
Three main reasons:
-
Babylonian astronomy (c. 2000 BCE):
- Seven visible "planets": Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn
- Each day dedicated to one celestial body
- Seven considered sacred number
-
Jewish religious tradition (c. 1500 BCE):
- Genesis: God created world in 6 days, rested on 7th (Sabbath)
- Fourth Commandment: "Remember the Sabbath day"
- Embedded in religious law for 3,000+ years
-
Global adoption:
- Christianity spread Sunday worship (resurrection day)
- Islam adopted 7-day week with Friday prayers
- Roman Empire standardized it (321 CE Constantine decree)
- Colonial expansion made it universal
Why not 5, 8, or 10 days? All attempts to change it failed (French 10-day, Soviet 5/6-day weeks) due to deep cultural and religious entrenchment.
How many weeks are in a year?
52.14 weeks in a standard 365-day year.
Calculation: 365 days ÷ 7 days/week = 52.14 weeks (52 weeks + 1 day)
More precisely:
- Common year (365 days): 52 weeks + 1 day
- Leap year (366 days): 52 weeks + 2 days
Practical implications:
- 52 "full weeks" per year
- Extra 1-2 days cause annual calendar drift
- Same date falls on different day of week each year
ISO week-numbering:
- Most years: Weeks 1-52
- Some years: Weeks 1-53 (when year has 53 Thursdays)
What is a work week?
A work week is the 5-day period from Monday-Friday when most businesses operate, totaling 40 hours (8 hours/day × 5 days) in the US standard.
Work week structure:
- Weekdays: Monday-Friday (5 days) - work/school days
- Weekend: Saturday-Sunday (2 days) - rest days
- 5-2 split: 5 days work, 2 days rest
Hours:
- US full-time: 40 hours per week standard
- France: 35 hours per week legal standard
- Part-time: 20-30 hours per week
- Overwork: 50-60+ hours per week
Variations:
- 4-day work week: Emerging trend (32-40 hours over 4 days)
- 6-day work week: Historical standard, still common in some countries
- Muslim countries: Friday-Saturday weekend (work Sunday-Thursday)
Origins:
- Industrial Revolution: Standardized factory schedules
- Labor movements: Won 5-day, 40-hour week (1926-1940 in US)
- Henry Ford: Pioneered 5-day, 40-hour week (1926)
- Fair Labor Standards Act (1938): Codified 40-hour week in US
What is the weekend?
The weekend is the 2-day period of rest at the end of the work week, typically Saturday and Sunday in Western countries.
Weekend structure:
- Saturday: First day off
- Sunday: Second day off, traditional Christian day of worship
- Purpose: Rest, recreation, family time, errands
Global variations:
- Western countries: Saturday-Sunday (majority of world)
- Muslim countries: Friday-Saturday or Friday-Sunday (historically)
- Saudi Arabia, UAE: Switched to Saturday-Sunday in 2022
- Iran: Friday only
- Israel: Friday-Saturday (aligns with Jewish Sabbath)
- Brunei, Bangladesh: Friday-Saturday
Origins:
- Jewish Sabbath: Saturday rest day (biblical commandment)
- Christian Sunday: Lord's Day (resurrection observance)
- Industrial era: Originally only Sunday off
- 1920s-1940s: Saturday added, creating "weekend"
- Labor advocacy: "Saturday half-day" became full day off
Cultural significance:
- "Thank God It's Friday" (TGIF)
- "Weekend warrior" (active on weekends)
- "Monday blues" (dreading return to work)
- Weekend social events, sports, entertainment
How many weeks are in a month?
Approximately 4.35 weeks in an average month.
Calculation:
- Average month = 30.44 days (365 ÷ 12)
- 30.44 days ÷ 7 days/week = 4.35 weeks
Actual variation:
- February: 4.0 weeks (28 days), 4.14 weeks (29 days, leap year)
- 30-day months: 4.29 weeks (April, June, September, November)
- 31-day months: 4.43 weeks (January, March, May, July, August, October, December)
Why not exactly 4 weeks?
- 4 weeks = 28 days
- Most months = 30-31 days
- 2-3 days "extra" per month
Implications:
- "Monthly" ≠ "every 4 weeks"
- Monthly salary ≠ 4 weekly salaries
- Rent is monthly (12 times/year), not 4-weekly (13 times/year)
What is a fortnight?
A fortnight is a period of 14 days or 2 weeks.
Origin:
- Old English: fēowertīene niht = "fourteen nights"
- Common in British English
- Less common in American English
Usage:
- UK: "I'll see you in a fortnight" (2 weeks from now)
- Australia/New Zealand: Common term
- Pay periods: "Fortnightly pay" = paid every 2 weeks
- Planning: "Fortnight holiday" = 2-week vacation
Related terms:
- Bi-weekly: Every 2 weeks (26 times per year)
- Semi-monthly: Twice per month (24 times per year)
- Fortnight = bi-weekly interval, not semi-monthly
Why do weekends exist?
Weekends exist due to religious tradition and labor reform:
Religious origins:
- Jewish Sabbath: Saturday rest day (biblical commandment, ~3,000 years old)
- Christian Sunday: Lord's Day, resurrection observance (2,000 years old)
- Both religions mandate one day of rest per week
Industrial era (1800s-1900s):
- Initially: 6-day work week, only Sunday off (Christian influence)
- Workers labored Monday-Saturday, 10-16 hours per day
- Exhausting, no family time
Labor reform (1900s):
- 1908: First 5-day work week proposed
- 1926: Henry Ford adopted 5-day, 40-hour week (factory efficiency + consumer spending)
- 1929: Great Depression led to work-sharing (reduce hours to employ more)
- 1938: Fair Labor Standards Act (US) established 40-hour week with overtime
- 1940: 5-day work week became US standard
Why 2-day weekend prevailed:
- Productivity: Workers more productive with adequate rest
- Consumer economy: Workers with free time spend money
- Family time: Social benefits
- Religious observance: Accommodates both Saturday (Jewish) and Sunday (Christian)
- Union advocacy: Labor movements fought for it
Modern trends:
- 4-day work week experiments (same hours, compressed)
- Flexible schedules: "Weekend" varies by individual
- Remote work blurs work-weekend boundaries
Can weeks start on different days?
Yes, weeks can start on either Sunday or Monday depending on cultural convention, though the 7-day cycle remains constant.
Two main systems:
1. Sunday-first (traditional Christian):
- Used in: United States, Canada, parts of Latin America
- Rationale: Sunday is the Lord's Day, "first day of week" in Christian tradition
- Calendars: US calendars show Sunday as leftmost column
- Biblical: Genesis creation starts with Sunday
2. Monday-first (ISO standard):
- Used in: Europe, Asia, Africa, Australia (most of world)
- ISO 8601 standard: Monday = day 1, Sunday = day 7
- Rationale: Work week starts Monday, weekend (Saturday-Sunday) grouped together
- Calendars: International calendars show Monday as leftmost column
Which is "correct"?
- Both are valid cultural conventions
- ISO 8601 standardizes Monday-first for international business/computing
- Work week universally Monday-Friday regardless
Computing:
- Programming: ISO 8601 standard (Monday = 1)
- Excel/Google Sheets: Can be configured either way
- Date/time libraries: Often use ISO standard
Practical impact:
- Minimal—everyone uses same 7-day cycle
- Only affects calendar layout and "first day" reference
- "Weekend" always means Saturday-Sunday (or local equivalent)
About Second (s)
What is the base unit of time in the SI system?
The second (s) is the base unit of time in the International System of Units (SI). It's one of the seven SI base units, alongside meter (length), kilogram (mass), ampere (current), kelvin (temperature), mole (amount of substance), and candela (luminous intensity).
All other time units (minute, hour, day, year) are derived from the second.
Why is the second defined using atoms?
The atomic definition provides a much more stable and precise standard than relying on Earth's rotation, which fluctuates.
Problems with astronomical definition:
- Earth's rotation slows by ~2 milliseconds per century (tidal friction)
- Seasonal variations affect day length
- Unpredictable fluctuations from earthquakes, atmospheric changes
- Accuracy limited to ~1 part per million
Advantages of atomic definition:
- Fundamental constant: Caesium-133 transition frequency is a property of nature
- Reproducible: Any caesium-133 atom behaves identically
- Stable: Unaffected by external conditions (temperature, pressure)
- Precise: Modern atomic clocks accurate to 1 second in 100 million years
Result: GPS, telecommunications, science, and technology require nanosecond precision impossible with astronomical timekeeping.
How many seconds are in a minute?
There are exactly 60 seconds in 1 minute.
This derives from ancient Babylonian base-60 (sexagesimal) mathematics, which established 60 as the standard division for time over 4,000 years ago.
Conversions:
- 1 minute = 60 seconds
- 2 minutes = 120 seconds
- 5 minutes = 300 seconds
- 10 minutes = 600 seconds
How many seconds are in an hour?
There are exactly 3,600 seconds in 1 hour.
Calculation:
- 1 hour = 60 minutes
- 1 minute = 60 seconds
- 1 hour = 60 × 60 = 3,600 seconds
Conversions:
- 1 hour = 3,600 seconds
- 2 hours = 7,200 seconds
- 12 hours = 43,200 seconds
- 24 hours (1 day) = 86,400 seconds
How many seconds are in a day?
There are 86,400 seconds in 1 day (24 hours).
Calculation:
- 1 day = 24 hours
- 1 hour = 3,600 seconds
- 1 day = 24 × 3,600 = 86,400 seconds
Breakdown:
- 24 hours × 60 minutes/hour × 60 seconds/minute = 86,400 seconds
Note: This assumes a standard 24-hour day. Due to Earth's rotation irregularities, actual solar days vary by milliseconds. Leap seconds are occasionally added to keep atomic time synchronized with Earth rotation.
How many seconds are in a year?
A standard 365-day year contains 31,536,000 seconds.
Calculation:
- 365 days × 24 hours/day × 60 minutes/hour × 60 seconds/minute
- = 365 × 86,400
- = 31,536,000 seconds
Variations:
- Leap year (366 days): 31,622,400 seconds
- Julian year (365.25 days, average): 31,557,600 seconds
- Tropical year (365.2422 days, Earth orbit): 31,556,925 seconds
Fun fact: The song "Seasons of Love" from Rent states "525,600 minutes" in a year, which equals 31,536,000 seconds (365 days).
What is a millisecond?
A millisecond (ms) is one-thousandth of a second: 0.001 seconds or 10⁻³ seconds.
Conversions:
- 1 second = 1,000 milliseconds
- 1 millisecond = 0.001 seconds
- 1 minute = 60,000 milliseconds
Common uses:
- Computer response times (1-100 ms)
- Network ping times (1-300 ms typical)
- Human reaction time (~200 ms)
- Video frame duration (60 FPS = 16.67 ms/frame)
- Stopwatch hundredths (0.01 s = 10 ms)
What is a nanosecond?
A nanosecond (ns) is one-billionth of a second: 0.000000001 seconds or 10⁻⁹ seconds.
Conversions:
- 1 second = 1,000,000,000 nanoseconds (1 billion)
- 1 millisecond = 1,000,000 nanoseconds (1 million)
- 1 microsecond = 1,000 nanoseconds
Reference points:
- Light travels 30 cm (1 foot) in 1 nanosecond
- Computer processor operations: ~0.2-1 nanosecond
- GPS timing precision: ~10 nanoseconds
- RAM memory access: ~50-100 nanoseconds
Grace Hopper's demonstration: Computer pioneer Grace Hopper famously distributed 30cm lengths of wire to represent "one nanosecond" (distance light travels in 1 ns) to illustrate the importance of speed in computing.
Why are there 60 seconds in a minute instead of 100?
The 60-second minute derives from ancient Babylonian base-60 (sexagesimal) mathematics developed around 3000 BCE, over 1,000 years before the decimal system.
Reasons for base-60:
1. High divisibility: 60 has 12 divisors: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60
- Easy to divide into halves, thirds, quarters, fifths, sixths
- 100 (decimal) has only 9 divisors: 1, 2, 4, 5, 10, 20, 25, 50, 100
2. Finger counting method:
- Count 12 finger segments (phalanges) on one hand using thumb
- Track count on other hand: 12 × 5 fingers = 60
3. Astronomical convenience:
- ~360 days per year ≈ 6 × 60
- Circle divided into 360 degrees (6 × 60)
- Babylonian astronomy used these divisions
4. Historical persistence: The system spread through Egyptian, Greek, and Roman civilizations and became too entrenched to change. When mechanical clocks developed in medieval Europe, they adopted the existing Babylonian time divisions.
Attempts to decimalize time:
- French Revolutionary Calendar (1793-1805): 10-hour day, 100-minute hour, 100-second minute
- Failed: Too difficult to change clocks, conversion from traditional system
- Result: We still use Babylonian base-60 for time, but base-10 (decimal) for most other measurements
How accurate are atomic clocks?
Modern atomic clocks are extraordinarily accurate:
Caesium atomic clocks (standard):
- Accuracy: 1 second in 100 million years
- Precision: Parts per trillion (10⁻¹²)
- Used in GPS satellites, national time standards
Caesium fountain clocks (advanced):
- Accuracy: 1 second in 300 million years
- Precision: Better than 10⁻¹⁵
- Used by metrology institutes (NIST, PTB, NPL)
Optical lattice clocks (state-of-the-art):
- Accuracy: 1 second in 15-30 billion years
- Precision: 10⁻¹⁸ to 10⁻¹⁹
- Use strontium, ytterbium, or aluminum ions
- So precise they detect gravitational time dilation across centimeters of height
Comparison:
- Quartz watch: 1 second in 1-10 days (10⁻⁵ accuracy)
- Mechanical watch: 1-10 seconds per day (10⁻⁴ to 10⁻⁵)
- Sundial: Minutes per day (10⁻³)
- Atomic clock: 1 second in 100 million years (10⁻¹⁶)
Why this matters: GPS requires 10-nanosecond precision; a 1-microsecond error causes 300-meter position errors.
What are leap seconds and why do we need them?
Leap seconds are occasional one-second adjustments added to Coordinated Universal Time (UTC) to keep it synchronized with Earth's rotation.
The problem:
- Atomic time (TAI): Runs at constant rate based on caesium clocks, unchanging
- Earth rotation (UT1): Slows gradually due to tidal friction (~2 milliseconds per day longer)
- Discrepancy: Accumulates ~1 second every 18-24 months
Solution:
- Add (or theoretically remove) 1 second on June 30 or December 31
- Keeps UTC within 0.9 seconds of Earth rotation time (UT1)
- 27 leap seconds added between 1972 and 2016
- No leap seconds since 2016 (Earth rotation has been slightly faster recently)
How it works: Instead of 23:59:59 → 00:00:00, the sequence is: 23:59:59 → 23:59:60 → 00:00:00 (leap second inserted)
Controversy:
- Problems: Computer systems, GPS, networks struggle with leap seconds (software bugs, crashes)
- Proposed solution: Abolish leap seconds, let UTC and UT1 drift apart
- Debate: Ongoing since 2000s; decision may be made in 2026-2030s
Current status: Leap seconds remain in use, but their future is uncertain.
Conversion Table: Week to Second
| Week (wk) | Second (s) |
|---|---|
| 0.5 | 302,400 |
| 1 | 604,800 |
| 1.5 | 907,200 |
| 2 | 1,209,600 |
| 5 | 3,024,000 |
| 10 | 6,048,000 |
| 25 | 15,120,000 |
| 50 | 30,240,000 |
| 100 | 60,480,000 |
| 250 | 151,200,000 |
| 500 | 302,400,000 |
| 1,000 | 604,800,000 |
People Also Ask
How do I convert Week to Second?
To convert Week to Second, enter the value in Week in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our time converter page to convert between other units in this category.
Learn more →What is the conversion factor from Week to Second?
The conversion factor depends on the specific relationship between Week and Second. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.
Can I convert Second back to Week?
Yes! You can easily convert Second back to Week by using the swap button (⇌) in the calculator above, or by visiting our Second to Week converter page. You can also explore other time conversions on our category page.
Learn more →What are common uses for Week and Second?
Week and Second are both standard units used in time measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our time converter for more conversion options.
For more time conversion questions, visit our FAQ page or explore our conversion guides.
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Verified Against Authority Standards
All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.
National Institute of Standards and Technology — Official time standards and definitions
Bureau International des Poids et Mesures — Definition of the SI base unit for time
Last verified: December 3, 2025