Time Unit Converter
Convert time between nanoseconds and years, including milliseconds for performance work and weeks for scheduling.
How it works
Time units up to the week are exact and convert through the second: 60 seconds to a minute, 60 minutes to an hour, 24 hours to a day, 7 days to a week. No ambiguity anywhere in that chain.
Months and years are the problem. A month is 28, 29, 30 or 31 days depending which one, and a year is 365 or 366. This converter uses the average — 30.44 days per month and 365.25 days per year — which is right for estimating durations and wrong for calendar arithmetic.
For anything involving actual dates, count the calendar rather than multiplying averages. The date difference tools handle leap years and month lengths properly; this one is for durations.
The formula
h → min
min = h × 60
min → h
h = min ÷ 60
Any pair in this family
result = value × (factor of source ÷ factor of target)
Every unit is defined against the s, so any combination converts in one step.
Worked examples
| Scenario | Working | Result |
|---|---|---|
| 2.5 hours to minutes | 2.5 × 60 | 150 minutes |
| 1 week to seconds | 7 × 24 × 3600 | 604,800 s |
| 1 year to days | Average year | 365.25 days |
When you'd use it
- Converting a duration for a schedule or estimate
- Turning milliseconds into a readable figure
- Working out how many hours are in a project of N days
- Converting timeouts and intervals in configuration
Common questions
How many days does this tool use for a month?
30.44 — the average month length across a year. That is correct for estimating a duration but wrong for calendar arithmetic, where you should count actual months. Use a date difference tool for real dates.
Why is a year 365.25 days here?
To account for leap years, which add a day roughly every four years. The true figure is slightly under 365.25, which is why century years are usually not leap years — but the difference is irrelevant over normal durations.
How many seconds are in a day?
86,400 — 24 × 60 × 60. This is exact for civil time, though very occasionally a leap second is added to keep clocks aligned with the Earth's rotation.
Is anything I enter sent anywhere?
No. Every conversion runs in your browser, so nothing you type is uploaded, logged or stored. There is no account and no record of what you converted.