Duration Converter

Convert a span of time between units — type into any field and the rest update to match.

How to use this tool

This converts a plain duration - a length of time on its own, not tied to any specific date - unlike the Date Calculator's Add/Subtract mode, which adds a duration to an actual date.

Exact units Milliseconds through weeks are exact, fixed-length conversions (a day is always 24 hours here, a week is always 7 days).
Months & years are averages A calendar month or year isn't a fixed length (28-31 days, or 365-366 days) - so "month" and "year" here use the conventional average (1 year = 365.25 days, 1 month = that ÷ 12) rather than any specific calendar month/year. For exact calendar arithmetic on a real date, use the Date Calculator instead.