Second to Decade Converter

Convert seconds to decades with our free online time converter.

Quick Answer

1 Second = 3.168874e-9 decades

Formula: Second × conversion factor = Decade

Use the calculator below for instant, accurate conversions.

Our Accuracy Guarantee

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.

Last verified: December 2025Reviewed by: Sam Mathew, Software Engineer

Second to Decade Calculator

How to Use the Second to Decade Calculator:

  1. Enter the value you want to convert in the 'From' field (Second).
  2. The converted value in Decade will appear automatically in the 'To' field.
  3. Use the dropdown menus to select different units within the Time category.
  4. Click the swap button (⇌) to reverse the conversion direction.
Share:

How to Convert Second to Decade: Step-by-Step Guide

Converting Second to Decade involves multiplying the value by a specific conversion factor, as shown in the formula below.

Formula:

1 Second = 3.1689e-9 decades

Example Calculation:

Convert 60 seconds: 60 × 3.1689e-9 = 1.9013e-7 decades

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.

What is a Second and a Decade?

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 decade is a unit of time equal to 10 consecutive years. The word derives from Ancient Greek "dekas" (δεκάς), meaning "a group of ten."

Duration in Other Units

1 decade equals:

  • 10 years (exactly)
  • 120 months (10 × 12 months)
  • ~520 weeks (10 × 52.18 weeks)
  • 3,652 days (common years) or 3,653 days (including leap years)
  • Average: 3,652.5 days (accounting for leap year cycle)
  • 87,660 hours (3,652.5 × 24)
  • 5,259,600 minutes (87,660 × 60)
  • 315,576,000 seconds (5,259,600 × 60)

Decade Boundaries: The 0 vs. 1 Debate

Popular usage (dominant):

  • 1980s = 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989 (years ending 0-9)
  • 1990s = 1990-1999
  • 2000s = 2000-2009
  • 2010s = 2010-2019
  • 2020s = 2020-2029

Formal reckoning (pedantic, rarely used):

  • Because there was no year 0 in the Gregorian calendar (1 BCE → 1 CE directly), decades "should" span 1-10:
    • 1st decade = 1-10 CE
    • 199th decade = 1981-1990
    • 200th decade = 1991-2000
    • 201st decade = 2001-2010

Reality: Popular usage (0-9) dominates overwhelmingly. When people say "the 1980s," they mean 1980-1989, not 1981-1990. Cultural identity, nostalgia, and historical analysis all use the 0-9 convention.


Note: The Second is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Decade belongs to the imperial/US customary system.

History of the Second and Decade

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:

  1. Earth's rotation is irregular: Tidal friction gradually slows rotation (~2 milliseconds per century)
  2. Seasonal variations: Earth's orbit affects day length by milliseconds
  3. Unpredictable fluctuations: Earthquakes, atmospheric changes affect rotation
  4. 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 Decade Concept

1. Ancient Origins: Base-10 Counting (Prehistoric)

The human preference for base-10 (decimal) counting stems from having 10 fingers, making groups of 10 natural for organization.

Early base-10 applications:

  • Ancient Egypt (~3000 BCE): Hieroglyphic numerals based on powers of 10
  • Ancient China (~1500 BCE): Decimal system in oracle bone inscriptions
  • Ancient Greece (~500 BCE): Decimal counting, though 12 and 60 also important
  • Ancient Rome: Latin "decem" (ten) gave root to "decade"

Why 10-year groups? Humans naturally organize time into manageable chunks. A year is too short for long-term trends, a century too long for human memory—a decade provides a Goldilocks timescale for pattern recognition.

2. Medieval and Renaissance Period (500-1600 CE)

"Decade" as general term:

  • Originally meant any group of 10 (10 books, 10 prayers, 10 beads)
  • Rosary decades: Catholic rosary divided into 5 decades (groups of 10 Hail Marys)
  • Literary decades: Collections of 10 stories or books (e.g., Boccaccio's "Decameron" = 10 days of stories)

Not yet specifically time-related: Medieval and Renaissance writers used "decade" for groupings, but not systematically for 10-year periods in historical analysis.

3. Enlightenment and Modern Historical Analysis (1700s-1800s)

Systematic historical periodization emerged:

  • 18th-century historians began organizing events by 10-year periods for analysis
  • Statistical thinking (late 1700s-1800s): Governments collected data in 10-year intervals
  • US Census (1790-present): Conducted every 10 years, reinforcing decade thinking
  • Economic cycles: Analysts noticed decade-scale patterns in markets, trade

Why decades gained prominence:

  1. Human lifespan scale: 10 years = noticeable change but within living memory
  2. Generational overlap: Enough time for trends to develop but not so long that witnesses die
  3. Data collection: Census and economic data naturally aligned with 10-year cycles
  4. Psychological salience: Decade birthdays (30, 40, 50, 60) mark life transitions

4. 20th Century: Decades as Cultural Identifiers (1900s-2000s)

The 20th century saw decades become powerful cultural and historical labels:

Early examples:

  • "The Gay Nineties" (1890s): Retrospective label for late Victorian optimism
  • "The Roaring Twenties" (1920s): Jazz Age, prohibition, economic boom, flapper culture
  • "The Thirties" (1930s): Great Depression, Dust Bowl, rise of fascism

Post-WWII decade labels (most influential):

  • "The Fifties" (1950s): Post-war prosperity, suburbs, rock and roll, Cold War begins
  • "The Sixties" (1960s): Civil rights, Vietnam War, counterculture, sexual revolution, moon landing
  • "The Seventies" (1970s): Disco, oil crisis, stagflation, Watergate, punk rock
  • "The Eighties" (1980s): Reagan/Thatcher, Cold War end, MTV, personal computers, Wall Street boom
  • "The Nineties" (1990s): Grunge, dot-com boom, end of Cold War, globalization, early internet

Why 20th-century decades are so culturally distinct:

  • Rapid change: Technology, politics, culture shifted dramatically every 10 years
  • Mass media: Radio (1920s-50s), TV (1950s-2000s), MTV (1980s-90s) amplified decade identity
  • Music genres: Each decade had distinctive music (jazz/20s, rock/50s, disco/70s, grunge/90s)
  • Fashion cycles: 10-year fashion trends reinforced decade boundaries
  • Political eras: Often aligned with decade boundaries (Kennedy/60s, Reagan/80s)

5. 21st Century: Digital Age Decades (2000s-Present)

New challenges to decade identity:

  • "The 2000s" = linguistic problem (no catchy name: noughties? aughts? two-thousands?)
  • Faster change: Internet, smartphones, social media accelerate cultural shifts
  • Decade labels less distinct: 2000s and 2010s harder to characterize uniquely
  • Nostalgia cycles: 1980s and 1990s nostalgia dominated 2010s-2020s

2000s decade naming attempts:

  • "Noughties" (British English): From "nought" (zero)
  • "Aughts" (American English): From "aught" (zero, archaic)
  • "Two-thousands": Clunky but functional
  • "The zeros": Rarely used

2010s:

  • "The twenty-tens" or "the tens": More natural linguistically
  • Cultural markers: Smartphones ubiquitous, social media dominance, streaming services

2020s (current decade):

  • "The twenties": Natural label, but overlaps with "Roaring Twenties" (1920s)
  • COVID-19 pandemic (2020-2023) defined early decade
  • Climate change, AI revolution, geopolitical shifts

Common Uses and Applications: seconds vs decades

Explore the typical applications for both Second (imperial/US) and Decade (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 decades

and Applications

1. Age and Life Stage Communication

"In my [decade]" describes life stage:

  • "In my twenties": Young adulthood, career building, dating/marriage
  • "In my thirties": Career advancement, family raising, homeownership
  • "In my forties": Peak earning years, midlife transitions
  • "In my fifties": Late career, empty nest, retirement planning
  • "In my sixties": Retirement, grandparenting, senior status

More specific than single age: "I'm in my early thirties" conveys life stage better than "I'm 32."

2. Historical Analysis and Research

Decade-by-decade comparison standard:

  • "Income in 1970 vs. 2020": 5-decade comparison
  • "Homicide rates declined every decade since 1990s": Decade-scale trend
  • "Technology adoption: 2000s smartphones, 2010s tablets, 2020s AI"

Academic papers often structured by decade:

  • "This study examines voting patterns across three decades (1980s-2000s)"

3. Goal Setting and Life Planning

"Where do you see yourself in 10 years?" = classic interview/life question

10-year planning horizons:

  • Personal goals: "Get promoted within a decade," "Be debt-free in 10 years"
  • Savings goals: "Save $100K over next decade"
  • Health goals: "Run marathon before I turn 40" (decade milestone)

Vision boards and bucket lists: Often include decade milestones (30th birthday trip, 40th marathon).

4. Demographic and Market Segmentation

Age groups by decade:

  • 18-29: Young adults (target for entry-level products, dating apps)
  • 30-39: Prime family/career demographic (target for houses, minivans, life insurance)
  • 40-49: Peak earning (target for luxury goods, college savings plans)
  • 50-59: Pre-retirement (target for wealth management, travel)
  • 60+: Seniors (target for retirement services, healthcare)

Market research: "Millennials in their thirties prefer [X], while Gen X in their fifties prefer [Y]."

5. Forecasting and Trend Prediction

"Next decade" predictions common:

  • Technology: "AI will transform work in the next decade"
  • Climate: "2020s critical decade for climate action"
  • Economics: "Inflation forecasts for the decade ahead"

Industry roadmaps: Auto industry "2030 targets" = decade-scale planning (all-electric by 2030).

6. Reunion and Anniversary Events

Class reunions every decade:

  • 10-year reunion: Compare life trajectories, still young
  • 20-year reunion: Mid-life, established careers/families
  • 30-year reunion: Late career, nostalgia peaks
  • 50-year reunion: Senior years, mortality awareness

Anniversary milestones: Companies, organizations celebrate 10th, 25th, 50th, 100th anniversaries.

7. Sports Records and Comparisons

"Athlete of the Decade" awards:

  • AP Athlete of the Decade: Michael Jordan (1990s), Tiger Woods (2000s), Lionel Messi (2010s)
  • Team dominance: "Yankees dominated baseball in 1990s," "Patriots dynasty in 2010s"

Decade statistics: "Home runs per decade in MLB" = long-term trend analysis.


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 Decade (dec)

1. How many years are in one decade?

Exactly 10 years. The word "decade" comes from Greek "dekas" (δεκάς), meaning "group of ten."

Other units:

  • 1 decade = 10 years = 120 months = ~3,652.5 days = 87,660 hours

2. How are decades typically named or referred to?

By tens digit: "The 1980s" (1980-1989), "the 2020s" (2020-2029).

Nicknames for famous decades:

  • 1920s: "The Roaring Twenties," "The Jazz Age"
  • 1950s: "The Fifties"
  • 1960s: "The Sixties," "The Swinging Sixties"
  • 2000s: "The Noughties" (UK), "The Aughts" (US), "The Two-Thousands"

3. Does a decade start with a year ending in 0 or 1?

Popular usage (dominant): Decades start with years ending in 0.

  • The 1980s = 1980-1989
  • The 2020s = 2020-2029

Formal reckoning (rarely used): Because there was no year 0, decades technically span 1-10.

  • The 199th decade = 1981-1990

Conclusion: Popular usage (0-9) dominates in all practical contexts.

4. What decade am I in if I'm 35 years old?

You're in your fourth decade of life.

Breakdown:

  • First decade: Birth (0) to 10th birthday (10) = ages 0-9
  • Second decade: Ages 10-19
  • Third decade: Ages 20-29
  • Fourth decade: Ages 30-39 ← You are here at age 35
  • Fifth decade: Ages 40-49

Mnemonic: Count the completed decades + 1. At age 35, you've completed 3 decades (0-10, 10-20, 20-30) and are in your 4th.

5. Is the decade an SI unit?

No. The decade is not part of the International System of Units (SI). The SI base unit for time is the second.

Non-SI time units commonly used:

  • Minute (60 seconds)
  • Hour (3,600 seconds)
  • Day (~86,400 seconds)
  • Year (~31.5 million seconds)
  • Decade (~315 million seconds)

Scientific contexts: Research often uses SI units like kiloyears (kyr = 1,000 years) or megayears (Myr = 1 million years) rather than decades.

6. How many days are in a decade?

Approximately 3,652.5 days (accounting for leap years).

Calculation:

  • 10 years × 365 days = 3,650 days
  • Plus ~2.5 leap days per decade = 3,652.5 days

Exact number varies: Depends on leap year distribution in the specific decade.

  • Decade with 2 leap years: 3,652 days
  • Decade with 3 leap years: 3,653 days

7. What's the difference between a decade and a generation?

Decade: Exactly 10 years, used for historical/cultural periodization.

Generation: Approximately 20-30 years, the average time between birth of parents and birth of their children.

Generations span multiple decades:

  • Baby Boomers (1946-1964): ~2 decades
  • Generation X (1965-1980): ~1.5 decades
  • Millennials (1981-1996): ~1.5 decades
  • Generation Z (1997-2012): ~1.5 decades

Key difference: Decade = fixed 10 years; generation = variable ~20-30 years based on demographic/cultural cohorts.

8. Why are decades important in history and culture?

Human-scale timescale: 10 years is long enough for significant change but short enough to remember/experience.

Pattern recognition: Decade groupings reveal trends invisible in year-by-year analysis.

Cultural identity: Decades serve as convenient labels for distinct eras ("the Sixties," "the Eighties").

Psychological salience: Decade milestones (10, 20, 30, 40) feel more significant than other ages.

Media influence: 20th-century mass media amplified decade identity through music, fashion, political eras.

9. What is a "lost decade"?

Economic term: A decade of economic stagnation or decline, minimal growth.

Famous examples:

  • Japan's Lost Decade (1990s): Asset bubble burst → prolonged recession
    • Actually extended into "Lost Two Decades" or "Lost Three Decades" (1990s-2010s)
  • Latin America's Lost Decade (1980s): Debt crisis → stagnation
  • US "Lost Decade" (2000s): Dot-com crash (2000) + Financial crisis (2008) = weak growth

Personal context: "Lost decade" can mean any 10-year period of personal stagnation or hardship.

10. How do I calculate how many decades between two years?

Formula: decades = (ending year - starting year) ÷ 10

Examples:

  • 1980 to 2020: (2020 - 1980) ÷ 10 = 4 decades (40 years)
  • 1995 to 2025: (2025 - 1995) ÷ 10 = 3 decades (30 years)
  • 2000 to 2018: (2018 - 2000) ÷ 10 = 1.8 decades (18 years)

11. What are decennial events?

Decennial = occurring every 10 years (once per decade).

Examples:

  • US Census: Conducted every 10 years (1790, 1800, ... 2020, 2030)
  • 10th anniversaries: Wedding, company founding, event commemoration
  • High school reunions: Often every 10 years (10th, 20th, 30th)

Etymology: From Latin "decennium" (decem = ten, annus = year).

12. How many decades in a century? In a millennium?

Century:

  • 1 century = 100 years = 10 decades

Millennium:

  • 1 millennium = 1,000 years = 100 decades

Conversions:

  • 5 decades = 50 years = 0.5 centuries
  • 20 decades = 200 years = 2 centuries = 0.2 millennia

Conversion Table: Second to Decade

Second (s)Decade (dec)
0.50
10
1.50
20
50
100
250
500
1000
2500
5000
1,0000

People Also Ask

How do I convert Second to Decade?

To convert Second to Decade, 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 Decade?

The conversion factor depends on the specific relationship between Second and Decade. 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 Decade back to Second?

Yes! You can easily convert Decade back to Second by using the swap button (⇌) in the calculator above, or by visiting our Decade to Second converter page. You can also explore other time conversions on our category page.

Learn more →

What are common uses for Second and Decade?

Second and Decade 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.

All Time Conversions

Second to MinuteSecond to HourSecond to DaySecond to WeekSecond to MonthSecond to YearSecond to MillisecondSecond to MicrosecondSecond to NanosecondSecond to CenturySecond to MillenniumSecond to FortnightSecond to Planck TimeSecond to ShakeSecond to Sidereal DaySecond to Sidereal YearMinute to SecondMinute to HourMinute to DayMinute to WeekMinute to MonthMinute to YearMinute to MillisecondMinute to MicrosecondMinute to NanosecondMinute to DecadeMinute to CenturyMinute to MillenniumMinute to FortnightMinute to Planck TimeMinute to ShakeMinute to Sidereal DayMinute to Sidereal YearHour to SecondHour to MinuteHour to DayHour to WeekHour to MonthHour to YearHour to MillisecondHour to MicrosecondHour to NanosecondHour to DecadeHour to CenturyHour to MillenniumHour to FortnightHour to Planck TimeHour to ShakeHour to Sidereal DayHour to Sidereal YearDay to SecondDay to MinuteDay to HourDay to WeekDay to MonthDay to YearDay to MillisecondDay to MicrosecondDay to NanosecondDay to DecadeDay to CenturyDay to MillenniumDay to FortnightDay to Planck TimeDay to ShakeDay to Sidereal DayDay to Sidereal YearWeek to SecondWeek to MinuteWeek to HourWeek to DayWeek to MonthWeek to YearWeek to MillisecondWeek to MicrosecondWeek to NanosecondWeek to DecadeWeek to CenturyWeek to MillenniumWeek to FortnightWeek to Planck TimeWeek to ShakeWeek to Sidereal DayWeek to Sidereal YearMonth to SecondMonth to MinuteMonth to HourMonth to DayMonth to WeekMonth to YearMonth to MillisecondMonth to MicrosecondMonth to NanosecondMonth to DecadeMonth to CenturyMonth to MillenniumMonth to FortnightMonth to Planck TimeMonth to ShakeMonth to Sidereal DayMonth to Sidereal YearYear to SecondYear to MinuteYear to HourYear to DayYear to WeekYear to MonthYear to MillisecondYear to MicrosecondYear to NanosecondYear to DecadeYear to CenturyYear to MillenniumYear to FortnightYear to Planck TimeYear to ShakeYear to Sidereal DayYear to Sidereal YearMillisecond to SecondMillisecond to Minute

Verified Against Authority Standards

All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.

NIST Time and Frequency

National Institute of Standards and TechnologyOfficial time standards and definitions

BIPM Second Definition

Bureau International des Poids et MesuresDefinition of the SI base unit for time

Last verified: December 3, 2025