Convert time units — seconds, minutes, hours, days, weeks, months, years.
| Unit | Name | Value |
|---|---|---|
| ms | Millisecond | 31536000000 |
| s | Second | 31536000 |
| min | Minute | 525600 |
| hr | Hour | 8760 |
| d | Day | 365 |
| wk | Week | 52.142857 |
| mo | Month (30d) | 12.166667 |
Formula: Day = Year × 365.2
Multiply any year value by 365.2 to get day.
Reverse: Year = Day × 0.002738
Common year values — factor: 1 yr = 365.2 d
| Year (yr) | Day (d) | Context |
|---|---|---|
| 1 yr | 365.2 d | One year |
| 2 yr | 730.5 d | Two years |
| 5 yr | 1,826 d | 5 years |
| 10 yr | 3,652 d | One decade |
| 25 yr | 9,131 d | Quarter century |
| 50 yr | 1.826e+04 d | Half century |
| 100 yr | 3.652e+04 d | One century |
| 200 yr | 7.305e+04 d | Two centuries |
| 500 yr | 1.826e+05 d | Half millennium |
| 1,000 yr | 3.652e+05 d | One millennium |
| 2,000 yr | 7.305e+05 d | 2 millennia |
| 5,000 yr | 1,826,000 d | Ancient Egypt |
| 1e+04 yr | 3,652,000 d | End of last ice age |
| 1e+05 yr | 36,520,000 d | H. sapiens timeline |
| 1,000,000 yr | 365,200,000 d | Early humans |
Years × 365.25 = days (Julian year). Round to × 365 for quick estimates.
1 yr = 365.25 d, 4 yr = 1,461 d (includes 1 leap year), 10 yr = 3,652.5 d.
Days ÷ 365.25 = 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.
The day (86,400 seconds) is defined by Earth's rotation period relative to the Sun. Ancient civilizations independently divided the day into 24 hours — Egyptians used sundials and water clocks as early as 1500 BCE.
Days are the fundamental unit of the Gregorian calendar and human biological rhythm (circadian cycle). Stock markets, shipping logistics, medication dosing, and agricultural planning all operate on daily cycles.
Interesting fact: A 'sidereal day' (Earth's rotation relative to stars) is 23 hours 56 minutes 4 seconds — about 4 minutes shorter than the 24-hour solar day we use.
Converting year to day 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 = 1826 d and 10 yr = 3652 d. For the reverse: 1 d = 0.002738 yr. The exact conversion factor is 1 yr = 365.2 d.
All conversions are performed in IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.