Gregorian to tabular Islamic (civil) date converter
The tabular Islamic calendar gives a fixed date from an arithmetic rule rather than moon sighting, useful for planning and historical references.
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How to use it
- Enter gregorian date.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Odd months have 30 days and even months 29; Dhu al-Hijjah has 30 days in 11 years of every 30 (2, 5, 7, 10, 13, 16, 18, 21, 24, 26, 29). JDN = day + ceil(29.5 × (month minus 1)) + 354 × (year minus 1) + floor((3 + 11 × year) / 30) + 1948439.
Example
Inputs: Gregorian date = 2026-10-01. Result: Converted date: 18 Rabi al-Thani 1448 AH; Day: 18; Month name: Rabi al-Thani.
Limits and caveats
- It can differ by one or two days from the Umm al-Qura calendar and from months started by moon sighting.
- Not suitable for officially fixing the start of Ramadan or Eid.
Questions about this tool
How does the tabular calendar differ from Umm al-Qura?
The tabular calendar is a fixed 30-year rule, while Umm al-Qura uses an astronomical rule based on sunset and moonset in Makkah, so they can differ by a day.
Why is it called civil?
It counts from Friday 16 July 622 CE, the civil epoch, rather than the astronomical epoch of Thursday 15 July.
How many days are in a tabular Islamic year?
354 in a common year and 355 in a leap year, so 10631 days in every 30-year cycle.