How does the date converter work?
This converter translates any date between the Hijri (lunar) calendar and the Gregorian (solar) calendar, in either direction, using an arithmetic algorithm (a tabular Hijri calendar) that runs entirely in your browser, with no data sent to a server.
Pick the conversion direction from the tabs above: Gregorian to Hijri, or Hijri to Gregorian.
How accurate is the result?
The official Hijri calendar used in Saudi Arabia (the Umm al-Qura calendar) relies on actual moon sighting or precise astronomical calculations of the moon's position at the start of each month, while this converter uses a fixed arithmetic algorithm (a tabular Islamic calendar) that does not account for sighting variation from month to month.
A margin of one to two days The result here is an approximation and may differ by one or two days from the official calendar, especially near the start of a lunar month. For important official or religious occasions, always check the officially announced calendar in your country.
The difference between the two calendars
| Property | Hijri calendar | Gregorian calendar |
|---|---|---|
| Based on | The moon's orbit around Earth | The Earth's orbit around the sun |
| Year length | About 354 days | 365 or 366 days (leap year) |
| Months | 12 lunar months (29 or 30 days) | 12 months of roughly fixed length |
| Common use | Religious occasions and the official calendar in some countries | International and general administrative use |
Because of the roughly 11-day difference in year length, the Hijri date corresponding to any fixed Gregorian date shifts backward by about that many days each year.
Frequently asked questions
Does the result match the official Umm al-Qura calendar exactly?
Approximately, but not always exactly. This calculation is purely arithmetic, while the official Umm al-Qura calendar sometimes accounts for additional astronomical data, so a one- or two-day difference can appear, especially near the start of a month.
Can I convert very old or far-future dates?
Yes, arithmetically, but accuracy decreases the further the date is from the present, due to accumulated differences from the real astronomical calendar.
Are the dates I enter stored anywhere?
No, every conversion happens entirely inside your browser, and no data is sent to any server.
Why do Hijri months have either 29 or 30 days?
A lunar month is actually about 29.5 days long, so months alternate between 29 and 30 days to approximate that average across the Hijri year.
Last updated: