Week to Century Converter
Convert weeks to centuries with our free online time converter.
Quick Answer
1 Week = 0.000192 centuries
Formula: Week × conversion factor = Century
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 Century Calculator
How to Use the Week to Century Calculator:
- Enter the value you want to convert in the 'From' field (Week).
- The converted value in Century 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 Century: Step-by-Step Guide
Converting Week to Century involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Week = 0.000191653 centuriesExample Calculation:
Convert 60 weeks: 60 × 0.000191653 = 0.0114992 centuries
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.
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View all Time conversions →What is a Week and a Century?
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
A century is a unit of time equal to 100 consecutive years. The word derives from Latin "centum" (one hundred).
Duration in Other Units
1 century equals:
- 100 years (exactly)
- 10 decades (100 ÷ 10)
- 1,200 months (100 × 12)
- ~5,217 weeks (100 × 52.17)
- 36,524 days (100 common years) or 36,525 days (accounting for ~25 leap years)
- Average: 36,525 days (100 × 365.25)
- 876,600 hours (36,525 × 24)
- 52,596,000 minutes (876,600 × 60)
- 3,155,760,000 seconds (52,596,000 × 60)
Century Boundaries: The 1 vs. 0 Debate
Formal reckoning (technically correct):
- 1st century: 1-100 CE
- 18th century: 1701-1800
- 19th century: 1801-1900
- 20th century: 1901-2000
- 21st century: 2001-2100
Why? Because there was no year 0 in the Gregorian calendar (1 BCE → 1 CE directly), the first century was years 1-100, not 0-99.
Popular usage (dominant in practice):
- 18th century: "The 1700s" (1700-1799)
- 19th century: "The 1800s" (1800-1899)
- 20th century: "The 1900s" (1900-1999)
- 21st century: "The 2000s onward" (2000-2099)
Reality: Popular usage dominates. When people say "20th century," they typically mean 1900-1999, not 1901-2000. The millennium celebration happened January 1, 2000, not January 1, 2001, despite formal correctness.
Note: The Week is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Century belongs to the imperial/US customary system.
History of the Week and Century
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
of the Century Concept
1. Ancient Origins: Roman Centuria (509 BCE - 27 BCE)
Roman military organization:
- Centuria (plural: centuriae) = Roman military unit of approximately 100 soldiers (later reduced to 80)
- Led by a centurion (centurio)
- Latin "centum" = one hundred
- 6 centuries = 1 cohort; 10 cohorts = 1 legion (~6,000 soldiers)
Early timekeeping:
- Romans used Ab urbe condita (AUC, "from the founding of the city") dating from Rome's legendary founding (753 BCE)
- No systematic use of "century" for 100-year periods yet
- Time organized by consulships, reigns, dynasties
2. Calendar Development and Anno Domini Dating (1 CE - 1582 CE)
Anno Domini (AD) system:
- Dionysius Exiguus (c. 525 CE): Calculated years from Jesus Christ's birth
- Introduced Anno Domini (AD, "in the year of the Lord") dating
- Critical error: No year 0 (went directly from 1 BCE to 1 CE)
- This creates century boundary confusion still debated today
Julian Calendar (46 BCE - 1582 CE):
- Julius Caesar introduced 365.25-day year (leap year every 4 years)
- Provided stable framework for long-term chronology
- Enabled systematic dating of events over centuries
Gregorian Calendar Reform (1582 CE):
- Pope Gregory XIII corrected Julian calendar drift
- Established modern calendar system still used today
- Removed 10 days (October 4, 1582 → October 15, 1582)
- Century years divisible by 400 are leap years (1600, 2000), others not (1700, 1800, 1900)
3. Renaissance and Enlightenment: Historical Periodization (1400s-1700s)
Systematic historiography emerged:
- 15th-16th centuries: Renaissance scholars developed historical chronologies
- 17th-18th centuries: Enlightenment historians systematized century-based periodization
- Edward Gibbon (Decline and Fall of the Roman Empire, 1776-1789): Used century-scale analysis
Why centuries became standard:
- Generational scale: ~4 generations per century = intergenerational change visible but comprehensible
- Administrative records: Tax records, census data, government documents accumulated over centuries
- Pattern recognition: 100-year scale reveals structural changes invisible in decade-scale analysis
- Round number psychology: Base-10 counting makes 100-year periods psychologically satisfying
Periodization labels emerged:
- "The 16th century" = 1500s Renaissance, Reformation
- "The 17th century" = 1600s Scientific Revolution, Baroque
- "The 18th century" = 1700s Age of Enlightenment, Industrial Revolution begins
4. 19th Century: Century as Historical Framework (1801-1900)
The "long 19th century" concept:
- Historians sometimes define as 1789-1914 (French Revolution to WWI)
- Captures coherent historical era despite not matching formal century boundaries
Major 19th-century transformations:
- Industrial Revolution (1760-1840): Steam power, factories, railroads
- Urbanization: Rural → urban population shift
- Imperialism: European colonial empires peak
- Scientific progress: Darwin, Maxwell, Mendel
- Political revolutions: 1848 Revolutions, unification of Germany/Italy
- Technological: Telegraph, telephone, photography, electricity
Century consciousness:
- People in 1800s increasingly thought in century-scale terms
- "The spirit of the 19th century" = common phrase
- Fin de siècle (end of century, 1890s-1900s) = cultural movement
5. 20th Century: Century of Extremes (1901-2000)
Eric Hobsbawm's "short 20th century" (1914-1991):
- WWI start to Soviet Union collapse
- Captures coherent historical narrative despite formal century boundaries
Major 20th-century transformations:
- World Wars: WWI (1914-1918), WWII (1939-1945)
- Ideological conflict: Fascism, Communism, Capitalism compete
- Cold War (1947-1991): US vs. USSR, nuclear arms race
- Decolonization: European empires disintegrate (1940s-1970s)
- Technological revolutions:
- Automobiles, airplanes (early 1900s)
- Nuclear energy (1940s)
- Computers (1940s-1950s)
- Space exploration (1950s-1960s)
- Internet (1990s)
- Mobile phones (1990s-2000s)
- Population explosion: 1.6 billion (1900) → 6.1 billion (2000)
- Medical advances: Antibiotics, vaccines, life expectancy doubled
- Environmental: Climate change, ozone depletion, biodiversity loss
Century labeling:
- "The American Century" (Henry Luce, 1941): US dominance of 20th century
- "The People's Century" (BBC, 1995): Mass politics, democracy spread
6. 21st Century: Digital Age and Beyond (2001-Present)
Millennium transition debate:
- Popular celebration: January 1, 2000 (Y2K)
- Formal start: January 1, 2001
- Most people celebrated 2000 despite pedantic correctness
21st-century defining features (so far):
- 9/11 attacks (2001): "War on Terror" begins
- Digital revolution: Smartphones ubiquitous (iPhone 2007)
- Social media: Facebook, Twitter, Instagram, TikTok
- Climate crisis: Accelerating global warming, extreme weather
- COVID-19 pandemic (2020-2023): Global disruption
- AI revolution: ChatGPT (2022), generative AI breakthroughs
- Geopolitical shifts: Rise of China, multipolar world
- Economic: 2008 Financial Crisis, wealth inequality
"21st-century skills": Digital literacy, critical thinking, adaptability
Common Uses and Applications: weeks vs centuries
Explore the typical applications for both Week (imperial/US) and Century (imperial/US) to understand their common contexts.
Common Uses for weeks
When to Use centuries
and Applications
1. Historical Analysis and Research
Century-by-century comparison:
- Economic growth: "19th-century industrialization vs. 20th-century information age"
- Warfare evolution: "19th-century muskets → 20th-century machine guns → 21st-century drones"
- Life expectancy trends: Analyzed century-by-century
Academic papers:
- "This study examines voting patterns across two centuries (1800s-1900s)"
- "Century-scale climate reconstructions"
2. Art, Literature, and Cultural Studies
Periodization:
- "18th-century literature": Age of Enlightenment, Voltaire, Swift, Johnson
- "19th-century novel": Dickens, Austen, Tolstoy, Dostoevsky
- "20th-century art": Impressionism, Cubism, Surrealism, Abstract Expressionism
Art history courses: Often organized by century ("Art of the 17th Century")
3. Genealogy and Family History
Tracing ancestry:
- 4-5 generations per century = century scale ideal for family trees
- "My great-great-grandfather lived in the 19th century"
- Immigration records, census data organized by century
Life stages across centuries:
- Born late 1800s, died mid-1900s = lived through two centuries
4. Climate and Environmental Science
Century-scale climate patterns:
- Medieval Warm Period (10th-13th centuries): Warmer than average
- Little Ice Age (14th-19th centuries): Cooler than average
- 20th-21st century warming: Anthropogenic climate change
Projections:
- "By end of 21st century, sea level rise 1-2 meters"
5. Economic and Development Studies
Long-term economic trends:
- 19th century: Agricultural → industrial economies
- 20th century: Industrial → service/information economies
- 21st century: Digital/knowledge economies
Development indicators: Tracked over centuries (literacy, GDP, poverty)
6. Philosophy and Long-Term Thinking
"Think in centuries":
- Long Now Foundation: 10,000-year thinking
- Contrast with short-term thinking (quarterly earnings, election cycles)
Philosophical movements:
- 18th century: Enlightenment rationalism
- 19th century: Romanticism, existentialism emerges
- 20th century: Postmodernism
7. Legal and Property Rights
Land ownership records:
- Property deeds reference century-old transactions
- "Century farms": Farms in same family 100+ years
Copyright:
- Life + 70 years = often extends into next century after author's death
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 Century (c)
1. How many years are in a century?
Exactly 100 years. The word "century" comes from Latin "centum" (one hundred).
Other units:
- 1 century = 100 years = 10 decades = 1,200 months = ~36,525 days
2. When did the 21st century begin?
Formal answer: January 1, 2001 (because there was no year 0, the 1st century was years 1-100, so the 21st century is 2001-2100).
Popular answer: January 1, 2000 (most people celebrated the new millennium in 2000, and colloquially refer to "the 2000s" as the start of the 21st century).
Reality: Both are used; formal definition is technically correct, but popular usage dominates in practice.
3. Why is the 1800s called the 19th century?
Because of how centuries are numbered:
- 1st century = years 1-100
- 2nd century = years 101-200
- 18th century = years 1701-1800
- 19th century = years 1801-1900 (the "1800s")
- 20th century = years 1901-2000 (the "1900s")
Rule: Century number = (hundreds digit + 1). So 1800s → century 18+1 = 19th century.
4. How many generations are in a century?
Approximately 4-5 generations, assuming ~20-25 years per generation.
Calculation:
- If generation = 25 years → 100 ÷ 25 = 4 generations per century
- If generation = 20 years → 100 ÷ 20 = 5 generations per century
Example: Great-great-grandparents often lived in a different century than you.
5. Is a century a standard unit in science?
No. The century is not part of the International System of Units (SI). The SI base unit for time is the second.
Scientific time units:
- Years (Julian year = 365.25 days exactly)
- Kiloyears (kyr): 1,000 years
- Megayears (Myr): 1,000,000 years
- Gigayears (Gyr): 1,000,000,000 years
Century usage: Common in history, demography, climate science, but not formal SI unit.
6. How many days are in a century?
Approximately 36,525 days (accounting for leap years).
Calculation:
- 100 years × 365 days = 36,500 days
- Plus ~25 leap days per century = 36,525 days total
Exact number varies: Depends on leap year distribution (Gregorian calendar: 97 leap years per 400 years).
7. What is the difference between centennial and bicentennial?
Centennial: 100th anniversary (1 century)
Bicentennial: 200th anniversary (2 centuries)
Other -ennial terms:
- Sesquicentennial: 150th anniversary (1.5 centuries)
- Tercentennial/Tricentennial: 300th anniversary (3 centuries)
- Quadricentennial: 400th anniversary (4 centuries)
- Quincentennial: 500th anniversary (5 centuries)
8. Can a person live in three different centuries?
Yes, but extremely rare.
Requirements:
- Born in one century (e.g., 1898, 19th century)
- Live through next century (1900s, 20th century)
- Live into third century (2000s, 21st century)
- Requires living 102+ years if born in last years of century
Example: Born December 1898 (19th century) → lived through 20th century (1901-2000) → died January 2001 (21st century) = lived in 3 centuries despite being only 102 years old.
9. What is a "long century" in history?
Historical concept: Period longer than 100 years but representing a coherent historical era.
Famous examples:
- "Long 19th century" (1789-1914): French Revolution to WWI start
- "Long 18th century" (1688-1815): Glorious Revolution to Waterloo
- "Short 20th century" (1914-1991): Conversely, WWI to USSR collapse = only 77 years but captures coherent era
Why useful: Historical eras don't align neatly with formal century boundaries; "long/short century" captures thematic unity.
10. How do I calculate how many centuries between two years?
Formula: centuries = (ending year - starting year) ÷ 100
Examples:
- 1500 to 2000: (2000 - 1500) ÷ 100 = 5 centuries (500 years)
- 1776 to 2024: (2024 - 1776) ÷ 100 = 2.48 centuries (~248 years)
- 1900 to 2100: (2100 - 1900) ÷ 100 = 2 centuries (200 years)
11. What is "fin de siècle"?
French phrase: "End of the century" (literally "end of era")
Historical meaning: Cultural period at end of 19th century (1890s-1900s) characterized by:
- Cultural pessimism mixed with optimism
- Decadence, Art Nouveau
- Anxiety about modernity
- Transition into new century
Modern usage: Any "end of century" cultural moment (Y2K was modern "fin de siècle").
12. How many centuries in a millennium?
10 centuries = 1 millennium
Conversions:
- 1 century = 0.1 millennia (100 years)
- 5 centuries = 0.5 millennia (500 years)
- 10 centuries = 1 millennium (1,000 years)
- 20 centuries = 2 millennia (2,000 years)
Conversion Table: Week to Century
| Week (wk) | Century (c) |
|---|---|
| 0.5 | 0 |
| 1 | 0 |
| 1.5 | 0 |
| 2 | 0 |
| 5 | 0.001 |
| 10 | 0.002 |
| 25 | 0.005 |
| 50 | 0.01 |
| 100 | 0.019 |
| 250 | 0.048 |
| 500 | 0.096 |
| 1,000 | 0.192 |
People Also Ask
How do I convert Week to Century?
To convert Week to Century, 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 Century?
The conversion factor depends on the specific relationship between Week and Century. 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 Century back to Week?
Yes! You can easily convert Century back to Week by using the swap button (⇌) in the calculator above, or by visiting our Century to Week converter page. You can also explore other time conversions on our category page.
Learn more →What are common uses for Week and Century?
Week and Century 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