Date Difference Calculator
Count elapsed calendar days between dates or add and subtract whole days without daylight-saving changes.
Your inputs stay in your browser.Use YYYY-MM-DD calendar dates, years 0001-9999. Offset counts are whole days from 0 to 3,000,000. Today uses your device-local date at the click. Drafts stay in memory only; refreshing clears them. Processing and exports stay local.
Enter values or try an example, then choose Calculate / Generate.
How to use Date Difference Calculator
Choose Between dates or Add / subtract days. Enter manual YYYY-MM-DD dates, then Calculate. Between dates can include the end date explicitly. Today reads your device-local date at the click; Swap reverses the two drafts.
Worked example
2024-02-28 to 2024-03-01 is 2 elapsed days, or 3 dates with both endpoints included. 2024-12-31 plus 1 day is 2025-01-01.
Rules and limits
Proleptic Gregorian calendar, years 0001-9999. Offsets are 0-3,000,000 whole days and may not leave the supported year range. An end before the start is an error. Weeks are seven-day groups, not ISO week numbers. This is not a legal-deadline, holiday or working-day calculator.
What should we improve next?
Help shape the next update to Date difference calculator. Tell us what would make it better for you.
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