Convert time units — seconds, minutes, hours, days, weeks, months, years.
| Unit | Name | Value |
|---|---|---|
| ms | Millisecond | 86400000 |
| s | Second | 86400 |
| min | Minute | 1440 |
| hr | Hour | 24 |
| wk | Week | 0.14285714 |
| mo | Month (30d) | 0.033333333 |
| yr | Year | 0.002739726 |
Formula: Year = Day × 0.002738
Multiply any day value by 0.002738 to get year.
Reverse: Day = Year × 365.2
Common day values — factor: 1 d = 0.002738 yr
| Day (d) | Year (yr) | Context |
|---|---|---|
| 1 d | 0.002738 yr | One day |
| 7 d | 0.01916 yr | One week |
| 14 d | 0.03833 yr | Two weeks |
| 30 d | 0.08214 yr | One month |
| 90 d | 0.2464 yr | One quarter |
| 180 d | 0.4928 yr | Half year |
| 365 d | 0.9993 yr | One year |
| 730 d | 1.999 yr | Two years |
| 1,825 d | 4.997 yr | 5 years |
| 3,652 d | 10 yr | One decade |
| 7,305 d | 20 yr | 20 years |
| 3.652e+04 d | 100 yr | One century |
| 3.652e+05 d | 1,000 yr | One millennium |
| 3,652,000 d | 1e+04 yr | 10,000 years |
| 36,520,000 d | 1e+05 yr | 100,000 years |
Days ÷ 365.25 = years (Julian). Round to ÷ 365 for quick estimates.
365 d ≈ 1 yr, 1,461 d = 4 yr (including leap year).
Years × 365.25 = days.
Plans project timelines and milestone durations in days using Gantt charts.
Calculates lead times, delivery windows, and inventory turnover in days.
Prescribes medication courses in days and tracks patient recovery timelines.
Plans crop cycles, irrigation schedules, and harvest windows in days.
Manages leave balances, probation periods, and notice periods in working days.
Calculates statutory deadlines, appeal windows, and contract terms in days.
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.
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.
Converting day to year 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 d = 0.01369 yr and 10 d = 0.02738 yr. For the reverse: 1 yr = 365.2 d. The exact conversion factor is 1 d = 0.002738 yr.
All conversions are performed in IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.