Time Converter
Enter an amount of time, pick the unit it is in and the unit you want, and the answer appears straight away. Thirteen units are supported, from nanoseconds to centuries.
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Created by the Reeliy Editorial Team. Last updated: Oct 19, 2026
Supported time units
The converter handles nanoseconds, microseconds, milliseconds, seconds, minutes, hours, days, weeks, months, quarters, years, decades and centuries. Every conversion runs through the same internal clock, so any unit can be turned into any other in one step.
Up to the week the units are exact multiples of a second. Beyond that, calendar units have no fixed length, so the converter uses averages.
| Unit | Length in seconds |
|---|---|
| Nanosecond (ns) | 0.000000001 |
| Microsecond (μs) | 0.000001 |
| Millisecond (ms) | 0.001 |
| Second (s) | 1 |
| Minute | 60 |
| Hour | 3,600 |
| Day | 86,400 |
| Week | 604,800 |
| Month (average) | 2,629,756.8 |
| Quarter (3 months) | 7,889,270.4 |
| Year (365.25 days) | 31,557,600 |
| Decade | 315,576,000 |
| Century | 3,155,760,000 |
How to convert time units
- Type the amount in the first box.
- Choose the unit of that amount, then the unit you want in the second drop-down.
- Read the answer. Results are rounded to 14 decimal places, and very small values are written in scientific notation such as 3.169e-11.
result = amount × (length of source unit in seconds) ÷ (length of target unit in seconds)
Common conversions with examples
Minutes to hours. Divide by 60. 6 minutes is 0.1 hours, and 8 hours is 480 minutes. For a decimal-to-clock version of this, see the decimal to time converter.
Seconds to minutes. Divide by 60. 90 seconds is 1.5 minutes.
Minutes to seconds. Multiply by 60. 45 minutes is 45 × 60 = 2,700 seconds.
Hours to days. Divide by 24. 36 hours is 1.5 days, and 168 hours is exactly one week.
Hours to seconds. Multiply by 3,600. 2.5 hours is 2.5 × 3,600 = 9,000 seconds.
| Seconds | Minutes | Hours | Days | |
|---|---|---|---|---|
| 1 minute | 60 | 1 | 0.0167 | 0.000694 |
| 1 hour | 3,600 | 60 | 1 | 0.0417 |
| 1 day | 86,400 | 1,440 | 24 | 1 |
| 1 week | 604,800 | 10,080 | 168 | 7 |
| 1 year | 31,557,600 | 525,960 | 8,766 | 365.25 |
Months, years and other calendar units
A month can be 28 to 31 days and a year is 365 or 366, so a calendar unit can only be converted exactly if you know which dates are involved. The converter therefore uses the averages in the table above. A year is 365.25 days, a quarter is three months, a decade is ten years and a century is a hundred years.
Conversions between months and years use the plain ratio of 12 months to a year, while conversions from months to days use 30.437 days per month. Because the two routes use slightly different averages, converting a unit forwards and then back can differ slightly, and answers involving months should be treated as approximations.
For exact gaps between two dates, use a calendar tool such as the days between dates calculator or the date and time duration calculator.
Other time conversions
- Decimal hours such as 7.75 to hours and minutes: decimal to time converter.
- Timesheet entries in both directions: timesheet converter.
- Computer timestamps counted in seconds since 1 January 1970: Unix timestamp converter.
- A clock time in another city: time zone converter.
Frequently asked questions
How many seconds are in a day?
86,400. That is 24 hours × 60 minutes × 60 seconds.
How many days are in a year for this converter?
365.25. The extra quarter day averages in leap years, so the figure is accurate over the long run but not for any single calendar year.
How do I convert minutes to hours?
Divide by 60. For example 90 minutes ÷ 60 = 1.5 hours.
Why do some results show an e, like 3.169e-11?
Very small results are written in scientific notation. 3.169e-11 means 3.169 × 10-11, a number with ten zeros after the decimal point before the digits begin.
References
- BIPM, The International System of Units (SI Brochure): the second
- IAU, Julian year of exactly 365.25 days
Cite this converter and page
If you use this page in your work, you can cite it as:
Reeliy Editorial Team. (2026). Time Converter. Reeliy. https://reeliy.com/converters/time-converter“Time Converter.” Reeliy, 2026, https://reeliy.com/converters/time-converter.