Hijri to Gregorian Date Converter

What is the Umm al-Qura calendar, and why do we use it?

The Umm al-Qura calendar is the official Hijri calendar of Saudi Arabia, issued by the King Abdulaziz City for Science and Technology (KACST). It is not a mathematical formula from which months are computed on the fly; it is a published table in which the start of every Hijri month is fixed in advance by precise astronomical calculation of the moon's birth and setting after sunset over Makkah.

This matters in practice: salaries, documents and official appointments in Saudi Arabia are all tied to this specific table. Tools using the "arithmetic Hijri calendar" (a 30-year cycle with 11 leap years) can drift from Umm al-Qura by a day or two in many months — trivial for a rough estimate, but serious when the date is a payday, a contract start, or a birthday. Our tool therefore uses the published table itself, and refuses any date outside its range (1318–1500 AH) instead of guessing it.

How is the table built? On the evening of the twenty-ninth, the moment of conjunction (the crescent's astronomical birth) and moonset relative to sunset in Makkah are calculated: if the moon sets after the sun, the new month starts the next day; otherwise the month is completed to thirty days. Published years in advance, the table lets this site show any date up to 1500 AH with confidence, and lets distant Hijri dates — contract ends, retirement entitlements — be planned without monthly announcements. One caveat: this construction serves civil use; the religious months follow their own sighting process, explained below.

How to convert from Hijri to Gregorian

To convert through the tool, follow these steps:

1) Select the "Hijri to Gregorian" direction. 2) Enter the day, the month by name, and the Hijri year. 3) Press "Convert date". The result shows the full Gregorian date with its weekday, your original Hijri date, the length of the month you chose, and the date's distance from today. The tool validates the day you entered: an error message appears immediately if the month has only 29 days and you enter day 30.

How to convert from Gregorian to Hijri

Select "Gregorian to Hijri", enter the date by day, month and year — or use the calendar picker — and press "Convert". This is the tool's most common use: finding a Hijri birth date, or seeing which Hijri month an upcoming Gregorian date falls in, such as the start of Ramadan.

A complete worked example: suppose a child was born on Sunday, 8 November 2026 CE, and we want the Hijri birth date for the records. Entering (8 / November / 2026) into the tool gives: Sunday, 28 Jumada al-Ula 1448 AH. Note: the weekday (Sunday) is the same in both calendars — it is the same day — and Jumada al-Ula in that year is 30 days long. In reverse, entering (28 / Jumada al-Ula / 1448) returns exactly 8 November 2026 — the two directions mirror because both read the same table.

Practical tip: for old family documents, check the year is inside the supported range. Dates older than 1318 AH (1900 CE) are outside the published table; any site showing a result for them uses an approximate arithmetic calendar that can be off by days.

Hijri vs Gregorian: the difference

The Hijri year is lunar: 12 months, each beginning with the birth of a new crescent, giving 354 days in a common year and 355 in a leap year. The Gregorian year is solar: 365 or 366 days — about 11 days more per year, which is why Hijri occasions move through the Gregorian seasons, crossing all of them in roughly 33 years, and why an age in Hijri is always greater than the same age in Gregorian: 32 full Gregorian years are about 33 Hijri years.

There is no fixed "quick conversion rule": the calendars' relationship slides continuously, and the only correct conversion passes day for day through the table — exactly what this tool does.

Hijri month names in order

The four sacred months are Muharram, Rajab, Dhu al-Qa'dah and Dhu al-Hijjah. The Umm al-Qura table sets each month's length (29 or 30 days) year by year, so never assume a fixed alternation: Safar has 29 days in one year, 30 in another. Our tool shows each month's length in the "Days in month" field with every result, and refuses a nonexistent day, such as day 30 of a 29-day month.

Why Ramadan and Eid can shift by a day

Umm al-Qura is a civil calendar calculated in advance, but the religious months — Ramadan, Shawwal and Dhu al-Hijjah — are announced in Saudi Arabia by crescent sighting on the evening of the twenty-ninth. If the sighting is confirmed, the month starts the next day; otherwise the month is completed to thirty days. So Ramadan or Eid may begin a day before or after the printed civil date — each correct in its own domain: the civil date for transactions, the announced date for worship. Our tool shows the civil date from the table, with a visible note when you convert dates connected to these months.

In practice, Saudi Arabia's Supreme Court calls on whoever sees the crescent to testify on the evening of the twenty-ninth: if established, the next day is the first of the month; otherwise it completes the month to thirty days. That is why official bodies publish dates such as the Eid al-Fitr holiday as "starting from such-and-such a day, to be confirmed by the moon sighting". Our advice: plan and book by the tool's date, keeping a one-day margin until the official announcement.

Common date-conversion mistakes

Three mistakes recur in manual conversion and on some websites. The first is assuming that Hijri months alternate regularly between 30 and 29 days, when the table can give two consecutive months the same length. The second is using "add 11 days per year" formulas as a conversion — an approximation unfit for a specific day. The third is ignoring that the religious day begins at sunset: someone born on the evening of a civil day may correspond, in religious reckoning, to the following Hijri day, while the civil calendar — and our tool — starts the day at midnight. Knowing these differences spares you the one-day errors that recur in CVs and old certificates.