Century to Decade Converter
Convert centuries to decades with our free online time converter.
Quick Answer
1 Century = 10 decades
Formula: Century × conversion factor = Decade
Use the calculator below for instant, accurate conversions.
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Century to Decade Calculator
How to Use the Century to Decade Calculator:
- Enter the value you want to convert in the 'From' field (Century).
- The converted value in Decade 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 Century to Decade: Step-by-Step Guide
Converting Century to Decade involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Century = 10 decadesExample Calculation:
Convert 60 centuries: 60 × 10 = 600 decades
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View all Time conversions →What is a Century and a Decade?
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.
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 Century 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 Century and Decade
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
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:
- Human lifespan scale: 10 years = noticeable change but within living memory
- Generational overlap: Enough time for trends to develop but not so long that witnesses die
- Data collection: Census and economic data naturally aligned with 10-year cycles
- 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: centuries vs decades
Explore the typical applications for both Century (imperial/US) and Decade (imperial/US) to understand their common contexts.
Common Uses for 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
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 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)
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: Century to Decade
| Century (c) | Decade (dec) |
|---|---|
| 0.5 | 5 |
| 1 | 10 |
| 1.5 | 15 |
| 2 | 20 |
| 5 | 50 |
| 10 | 100 |
| 25 | 250 |
| 50 | 500 |
| 100 | 1,000 |
| 250 | 2,500 |
| 500 | 5,000 |
| 1,000 | 10,000 |
People Also Ask
How do I convert Century to Decade?
To convert Century to Decade, enter the value in Century 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 Century to Decade?
The conversion factor depends on the specific relationship between Century 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 Century?
Yes! You can easily convert Decade back to Century by using the swap button (⇌) in the calculator above, or by visiting our Decade to Century converter page. You can also explore other time conversions on our category page.
Learn more →What are common uses for Century and Decade?
Century 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.
Helpful Conversion Guides
Learn more about unit conversion with our comprehensive guides:
All Time Conversions
Other Time Units and Conversions
Explore other time units and their conversion options:
- Second (s) • Century to Second
- Minute (min) • Century to Minute
- Hour (h) • Century to Hour
- Day (d) • Century to Day
- Week (wk) • Century to Week
- Month (mo) • Century to Month
- Year (yr) • Century to Year
- Millisecond (ms) • Century to Millisecond
- Microsecond (μs) • Century to Microsecond
- Nanosecond (ns) • Century to Nanosecond
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