Time & Duration Converter
Convert between milliseconds, seconds, minutes, hours, days, weeks, average months, and years in one place.
Stable formula
This calculator uses a stable mathematical formula. Always verify the values you enter.
- Accuracy level
- High when inputs and units are correct.
- Last reviewed
- July 9, 2026
- Formula or source
- Stable mathematical formula explained on the page.
- Guide reading time
- 2 min
- Confidence
- High for the stated calculation.
- Result type
- Formula result, not an official certification.
Do not use for: Cases with missing data, unclear units, or a required professional certification.
One converter instead of dozens of pages
Enter a value, choose the source and target units, and get an instant result. Switch units on the same screen without opening another calculator.
The calculation runs locally in your browser and does not send your inputs to a server.
๐ก Useful Tips
- Seconds, minutes, hours, days, and weeks use fixed lengths.
- Months and years use average lengths and should not replace a calendar date-difference calculation.
Frequently Asked Questions
How do I use the Time & Duration Converter?
Enter the relevant values in the fields, and the calculator returns a result using the formula and rules documented on the page.
Are my inputs stored?
No. The calculation runs in the browser, and the entered values are not sent to the server for the calculation.
When should I recalculate?
Recalculate whenever the inputs, units, or assumptions change.
What to check next
The result is a starting point. For a better picture, continue to a related calculator or read a short guide that explains the assumptions.