Calendar Utility
Date Calculator
Calculate days between dates or add and subtract whole calendar days.
Date difference
Add or subtract days
Method
Date differences use UTC date-only timestamps, avoiding daylight-saving clock-hour changes. Add/subtract operations use calendar dates and whole-day increments.
Worked examples
- January 1 to January 31, 2026 = 30 calendar days.
- Adding 30 days to January 1, 2026 gives January 31, 2026.
- Subtracting one day from March 1, 2026 gives February 28, 2026.
Privacy
All date arithmetic runs locally in the browser.
Limitations
This tool does not apply business-day, holiday, legal-deadline, time-zone, or jurisdictional rules.
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