Second to Century Converter
Convert seconds to centuries with our free online time converter.
Quick Answer
1 Second = 3.168874e-10 centuries
Formula: Second × 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.
Second to Century Calculator
How to Use the Second to Century Calculator:
- Enter the value you want to convert in the 'From' field (Second).
- 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 Second to Century: Step-by-Step Guide
Converting Second to Century involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Second = 3.1689e-10 centuriesExample Calculation:
Convert 60 seconds: 60 × 3.1689e-10 = 1.9013e-8 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.
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Need to convert to other time units?
View all Time conversions →What is a Second and a Century?
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)
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 Second 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 Second and Century
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
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: seconds vs centuries
Explore the typical applications for both Second (imperial/US) and Century (imperial/US) to understand their common contexts.
Common Uses for 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
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 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.
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: Second to Century
| Second (s) | Century (c) |
|---|---|
| 0.5 | 0 |
| 1 | 0 |
| 1.5 | 0 |
| 2 | 0 |
| 5 | 0 |
| 10 | 0 |
| 25 | 0 |
| 50 | 0 |
| 100 | 0 |
| 250 | 0 |
| 500 | 0 |
| 1,000 | 0 |
People Also Ask
How do I convert Second to Century?
To convert Second to Century, enter the value in Second 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 Second to Century?
The conversion factor depends on the specific relationship between Second 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 Second?
Yes! You can easily convert Century back to Second by using the swap button (⇌) in the calculator above, or by visiting our Century to Second converter page. You can also explore other time conversions on our category page.
Learn more →What are common uses for Second and Century?
Second 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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Other Time Units and Conversions
Explore other time units and their conversion options:
- Minute (min) • Second to Minute
- Hour (h) • Second to Hour
- Day (d) • Second to Day
- Week (wk) • Second to Week
- Month (mo) • Second to Month
- Year (yr) • Second to Year
- Millisecond (ms) • Second to Millisecond
- Microsecond (μs) • Second to Microsecond
- Nanosecond (ns) • Second to Nanosecond
- Decade (dec) • Second to Decade
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