Date Difference Calculator
Calculate the exact number of days, weeks, months and years between any two dates. Free, instant, no signup.
What is Date Difference Calculator?
The Date Difference Calculator finds the exact gap between any two dates — in days, weeks, months, and years simultaneously. Useful for project deadlines, contract durations, event countdowns, billing periods, and any time you need to know exactly how long something took or how long until something happens.
The tool handles month-length differences, leap years, and cross-year calculations automatically. Pick a start and end date and all the breakdowns appear instantly.
Runs entirely in your browser — no data is sent anywhere.
How to use
Frequently asked questions
The calculation counts the difference between dates (end minus start), so it does not double-count either endpoint. Add 1 to the day count if you need to include both endpoints.
Yes. The tool uses JavaScript's native Date object which accounts for leap years and varying month lengths automatically.
Yes. If the end date is before the start date, the result will show a negative number of days.