Duration Converter
Convert durations between seconds, minutes, hours, days, weeks, months, and years with clear assumptions.
Enter a duration amount, choose its unit, and convert it to another unit or a full table of common elapsed-time units. The converter runs locally in your browser and calls out the assumptions used for months and years.
Use a non-negative number. Commas and scientific notation are accepted for large values.
Only month, quarter, and year conversions use this assumption. Seconds through weeks use fixed elapsed-time lengths.
How it works
The converter first expresses your amount as elapsed seconds, then divides by the target unit length. Nanoseconds through weeks use fixed elapsed-time definitions, such as 60 seconds per minute and 24 hours per day.
Months, quarters, and years are not fixed elapsed-time units on real calendars. The default average Gregorian option uses 365.2425 days per year and one twelfth of that year for a month. The fixed planning option uses 365-day years and 30-day months when you need simpler estimates.
Use this tool for elapsed-time estimates, runbooks, service-level targets, lab notes, and planning math. For the exact difference between two calendar dates, especially across daylight-saving changes or variable month lengths, use a date/time difference calculator.
