Convert time units — seconds, minutes, hours, days, weeks, months, years, nanoseconds and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 yr | 0.0001 dec | |
| 0.01 yr | 0.001 dec | |
| 0.1 yr | 0.01 dec | |
| 1 yr | 0.1 dec | |
| 5 yr | 0.5 dec | |
| 10 yr | 1 dec | |
| 50 yr | 5 dec | |
| 100 yr | 10 dec | |
| 1000 yr | 100 dec |
Formula: Decade = Year × 0.1
Multiply any year value by 0.1 to get decade.
Reverse: Year = Decade × 10
Common year values — factor: 1 yr = 0.1 dec
| Year (yr) | Decade (dec) | Context |
|---|---|---|
| 1 yr | 0.1 dec | One year |
| 2 yr | 0.2 dec | Two years |
| 5 yr | 0.5 dec | 5 years |
| 10 yr | 1 dec | One decade |
| 25 yr | 2.5 dec | Quarter century |
| 50 yr | 5 dec | Half century |
| 100 yr | 10 dec | One century |
| 200 yr | 20 dec | Two centuries |
| 500 yr | 50 dec | Half millennium |
| 1,000 yr | 100 dec | One millennium |
| 2,000 yr | 200 dec | 2 millennia |
| 5,000 yr | 500 dec | Ancient Egypt |
| 1e+04 yr | 1,000 dec | End of last ice age |
| 1e+05 yr | 1e+04 dec | H. sapiens timeline |
| 1,000,000 yr | 1e+05 dec | Early humans |
Years ÷ 10 = decades. Exact.
10 yr = 1 decade, 100 yr = 10 decades = 1 century.
Decades × 10 = years.
Models multi-year revenue forecasts, DCF valuations, and amortization schedules.
Designs infrastructure with 20-50 year horizons for roads, utilities, and buildings.
Calculates life expectancy, annuity durations, and policy terms in years.
Measures stellar distances in light-years and planetary orbital periods in years.
Analyzes temperature records and climate projections spanning decades and centuries.
Tracks employee tenure, pension vesting schedules, and anniversary milestones in years.
The year (approximately 365.25 days) is defined by Earth's orbital period around the Sun. Julius Caesar introduced the Julian calendar (365.25 days) in 45 BCE; Pope Gregory XIII refined it to the Gregorian calendar in 1582 to correct accumulated drift.
Years organize human civilization: fiscal years, academic years, election cycles, and long-term planning. The Julian year (exactly 365.25 days = 31,557,600 seconds) is used as a standard in astronomy and this converter.
Interesting fact: A year on Venus is shorter than its day — Venus takes 225 Earth days to orbit the Sun but 243 Earth days to rotate once. A year on Neptune lasts 164.8 Earth years.
A decade is exactly 10 years, derived from the Greek deka (ten). Decades are used informally to describe cultural eras, technological generations, and historical periods.
Decades organize human cultural memory: 'the Roaring Twenties', 'the Swinging Sixties', 'the Digital Nineties'. Economic and geopolitical cycles are often analyzed in decade-long windows.
Interesting fact: The first decade of a century technically runs from year 1 to year 10 (not year 0 to year 9), making the 2000s decade 2001–2010 — though popular culture treats 2000–2009 as 'the 2000s'.
Converting year to decade is a common task across science, engineering, and everyday planning. The time scale spans from nanoseconds in computing to centuries in history, and having accurate conversions helps when comparing measurements across different systems or disciplines.
As a quick reference: 5 yr = 0.5 dec and 10 yr = 1 dec. For the reverse: 1 dec = 10 yr. The exact conversion factor is 1 yr = 0.1 dec.
All conversions are performed in IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.