Time Duration Calculator.
Dates, holiday lists and durations remain in this browser. Add, subtract and normalize hours, minutes, seconds and milliseconds. Uses explicit date-only Gregorian rules and independent local verification.
- ✓Runs in your browser
- ✓No account required
- ✓Verified output
Use Time Duration Calculator
Private in this browser. Dates, durations and user-supplied holiday lists stay in this browser.
Verified result
Download resultHow it works
- 01
Enter dates or elapsed durations and select the rules.
- 02
Run the bounded local calculation.
- 03
Review the calendar rules before downloading the verified result.
Frequently asked questions
Does this use my time zone?
No. Date arithmetic is deliberately independent of time zones and daylight-saving changes.
Does Time Duration Calculator upload my data?
Time Duration Calculator runs locally in your browser. Dates, durations and user-supplied holiday lists stay in this browser.
What output does Time Duration Calculator create?
Time Duration Calculator creates Json output after the result passes its local verification checks.