How to use this calculator
- For Gregorian → Hijri: pick any Gregorian date in the first field.
- For Hijri → Gregorian: enter the Hijri day, month number and year in the lower fields.
- Click Calculate. Both conversions, and today's date in both calendars, are shown together.
Formula — how it is calculated
The Hijri calendar is purely lunar: twelve months of 29 or 30 days make a year of 354 or 355 days — about 11 days shorter than the solar Gregorian year. That is why Ramadan and the Eids move earlier by roughly 11 days each Gregorian year and travel through all the seasons over about 33 years.
There are several calculated variants of the Hijri calendar. This converter uses Umm al-Qura, the official calendar of Saudi Arabia, calculated in advance from astronomical rules for Makkah and used on Saudi official documents; Pakistani NADRA documents and most Gulf civil references follow the same system. Your browser computes it directly using the internationalised Umm al-Qura calendar built into modern devices, and the reverse conversion searches that same calendar day by day, so the two directions always agree with each other.
One honest limitation: religious observance is set by moon sighting, not by calculation. The announced start of Ramadan or Eid in your country can differ from the calculated Umm al-Qura date by one day, occasionally two. Use this converter for documents, planning and everyday conversion — and confirm worship dates against your local authority's announcement.
Worked example
Take 13 November 2026. In the Umm al-Qura calendar that day is 3 Jumada al-akhirah 1448 AH — the sixth Hijri month, also written Jumada II. Converting back, 3/6/1448 AH returns exactly 13 November 2026, a Friday. Another everyday example: an iqama or contract expiry written as 1 Ramadan 1448 AH converts to 8 February 2027 in the Gregorian calendar (calculated date — the observed start of Ramadan may be announced a day either side).
Frequently asked questions
Which Hijri calendar does this converter use?
The Umm al-Qura calendar — the official calculated calendar of Saudi Arabia, also used for most Gulf civil and official purposes. It is computed by your browser's built-in international calendar, so conversions work offline too.
Why can the Hijri date differ by a day in my country?
Calculated calendars fix month lengths in advance, while religious months begin on the sighting of the crescent moon, announced by each country's authority. A one-day difference (rarely two) between the calculated date and the observed date is normal.
How many days are in a Hijri year?
354 days in a common year and 355 in a leap year — about 11 days fewer than a Gregorian year, which is why Islamic dates move through the seasons.
How do I convert a Hijri birthday to a Gregorian date?
Enter the Hijri day, month and year in the lower fields and click Calculate. Because a Hijri year is shorter, a person's Hijri age is slightly higher than their Gregorian age — roughly one extra year every 33 years.
Is the Umm al-Qura conversion exact for official documents?
For dates within the Umm al-Qura published range (roughly 1318–1500 AH / 1900–2077 CE) it matches the official Saudi calendar. Always double-check a legally critical date against the issuing authority.