Time Unit Converter
Convert a duration between milliseconds, seconds, minutes, hours, days, weeks, months, and years, all at once.
Recommended Settings
Pro Tips
- •Months and years use average lengths (30.44 and 365.25 days) since those units don't have a single fixed length in real calendars
- •All conversions update live as you change either the value or the unit
- •Useful for converting a duration found in code (often in milliseconds or seconds) into a more human-readable unit
- •For calculating the difference between two specific calendar dates instead of a plain duration, use Date Difference instead
Most Popular
Most users convert between seconds, minutes, and hours for everyday duration calculations
When to Use This Tool
Convert a timeout or interval value between the units your code or config file expects.
Compare two durations expressed in different units on equal footing.
Convert time durations for a school assignment or written report.
Convert a process duration in seconds into more intuitive hours or days.
How It Works
Convert your entered value and unit into a common base unit of seconds
Convert that total back into every other supported unit
Display all the equivalent values together, updating live as you change the input
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side unit conversion arithmetic for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
Why are months and years approximate?
Calendar months range from 28 to 31 days and years vary slightly due to leap years, so there's no single fixed length - this tool uses commonly accepted averages (30.44 days per month, 365.25 days per year).
Is this the same as calculating the difference between two dates?
No, this converts a plain duration (like '3 hours') between units. For finding the difference between two specific calendar dates, use the Date Difference tool instead.
Is my data sent to a server?
No. The conversion happens entirely in your browser.
Can I convert a negative duration?
Yes, entering a negative value converts proportionally in the negative direction across all units.
How precise are the results?
Results are shown to up to 6 decimal places, which is more than enough precision for virtually any practical use case.