Everyday tools · on your device
Date difference calculator and date arithmetic
Find elapsed days and calendar duration, or add/subtract years, months and days in Gregorian or Umm al-Qura.
Range: 1300–1600 AH / 1882-11-12 to 2174-11-25. Enter year-month-day.
- Duration in selected calendar
- 0 years, 0 months, 0 days
- Day count
- 0
Processing stays in your browser. We neither transmit nor store your inputs.
How to use this tool
- Select a calendar and operation: date difference or adding a duration. Use negative offsets to subtract.
- Day counts exclude the start and include the end by default. Inclusive mode adds the start. Weekend exclusion removes Friday/Saturday only; public holidays are not deducted.
- Years/months are added first, clamping to month-end when needed; days are added afterward.
- We use the ICU 78.1 Umm al-Qura table for 1300–1600 AH: 1882-11-12 to 2174-11-25. Dates outside this range are rejected, without another calendar method. Software validation against ICU is not government certification.
Unicode ICU · Umm al-Qura 78.1 (new tab)Sources reviewed: October 16, 2026
A few useful answers
Is this a legal deadline?
No. This calculates dates without legal deadline or holiday rules.
How are day boundaries and conversion defined?
Conversions use civil dates without a time: no sunset rollover or dependency on your device timezone. Today uses Riyadh time. Religious moon-sighting determinations can differ from calculated calendars.
Are my inputs stored?
No. Calculations and files stay in your browser. Shared tool links contain no entered details.