Converter hub
Time Converter
Time conversions use fixed definitions for seconds and days. Months and years are averages here — a calendar month varies from 28 to 31 days. Pick a pair below or open the page for the exact factor, a worked example and a full chart.
Units in this category
Time conversions use fixed definitions for seconds and days. Months and years are averages here — a calendar month varies from 28 to 31 days.
| Unit | Symbol | Definition |
|---|---|---|
| Years | yr | A Julian year is 365.25 days (31,557,600 seconds); calendar years vary. |
| Months | mo | A month here is the average Julian month of 30.4375 days (2,629,800 seconds). |
| Weeks | wk | A week is exactly seven days, or 604,800 seconds. |
| Days | d | A day is 24 hours, or 86,400 seconds, ignoring leap seconds. |
| Hours | hr | An hour is 60 minutes, or 3,600 seconds. |
| Minutes | min | A minute is 60 seconds. |
| Seconds | s | The second is the SI base unit of time, defined by the caesium hyperfine transition. |
| Milliseconds | ms | A millisecond is one thousandth of a second, common in latency and timing specs. |
All time conversions
Every listed pair has its own page with the formula, examples and a chart. Choose the starting unit:
Years (yr)
Months (mo)
Weeks (wk)
Milliseconds (ms)
Frequently asked questions
How many time units are supported?
8 units, which gives 14 one-way conversions.
Are the factors exact?
They follow SI and international definitions. Where a unit is approximate by nature (for example Mach, months or fuel economy), the page says so.
Can I convert in both directions?
Yes. Every pair page has a swap link and the calculator accepts any decimal value.