How to use the converter
Type an amount in the Value box, choose the unit you have and the unit you want, and press Convert. The swap button flips the two units, and a table below the result shows the same length of time in all fourteen units. The converter starts on days to hours.
This tool converts a length of time from one unit to another. To add times together or to find the time between two dates, use a time or date calculator instead.
Unit definitions
- Nanosecond (ns), microsecond (µs) and millisecond (ms): one billionth, one millionth and one thousandth of a second.
- Minute = 60 seconds, hour = 60 minutes = 3,600 seconds, day = 24 hours = 86,400 seconds.
- Week = 7 days and fortnight = 14 days.
- Year = 365.2425 days, the average Gregorian year. The Gregorian calendar has 97 leap years in every 400 years, so its years average 365 + 97/400 = 365.2425 days, which is 31,556,952 seconds.
- Month = one twelfth of that average year: 365.2425 ÷ 12 = 30.436875 days, or 2,629,746 seconds. Real calendar months have 28 to 31 days; this is their long-run average.
- Decade, century and millennium = 10, 100 and 1,000 average Gregorian years.
To convert, the value is multiplied by the length of the starting unit and divided by the length of the target unit.
Worked examples
- 2.5 days to hours: 2.5 × 24 = 60 hours.
- 1 year to minutes: 365.2425 × 1,440 = 525,949.2 minutes.
- 1 year to weeks: 365.2425 ÷ 7 ≈ 52.1775 weeks.
- 1 month to hours: 30.436875 × 24 = 730.485 hours.
- 1 billion seconds to years: 1,000,000,000 ÷ 31,556,952 ≈ 31.69 years.
Good to know
- Because months and years are averages, results in those units will not match a specific calendar period exactly. For example, February 2025 has 28 days and a common year has 365, not 365.2425. If you need the exact number of days between two dates, count them with a date calculator.
- A day here is always 86,400 seconds. Daylight saving changes and leap seconds are ignored.
- Results show up to six decimal places; very small values, such as a nanosecond expressed in years, are written in scientific notation.
- A length of time cannot be negative. Zero is accepted.