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Calculate Hijri age with Umm al-Qura or the Islamic civil calendar from Gregorian or Hijri dates, with conversion comparison and next birthday.
Last updated: July 22, 2026
Enter Gregorian or Hijri dates, choose the calendar convention, compare both systems, and find the next Hijri birthday.
Guide
The Islamic calendar contains twelve lunar months and averages about 354 days, roughly eleven days shorter than a Gregorian solar year. A person therefore completes Hijri years faster, and the numerical Hijri age gradually becomes higher than the Gregorian age over a lifetime.
The calculator accepts two Gregorian dates or two Hijri year-month-day dates. Hijri input is converted to its corresponding Gregorian date under the selected convention before age, elapsed days, anniversaries, and the alternate-calendar comparison are calculated.
Umm al-Qura is the Saudi convention exposed by the browser's ECMAScript Intl implementation and Unicode CLDR calendar data. Islamic civil is a fixed arithmetic calendar with repeatable 29- and 30-day month rules. The page calculates both for the same elapsed Gregorian days so a boundary difference is visible instead of hidden; it does not claim to reproduce a local crescent-sighting announcement.
The primary result borrows the actual length of the preceding month in the selected calendar and checks the next birthday date. It does not estimate age by dividing elapsed days by 354.367, although total elapsed days and completed Gregorian years remain visible for comparison.
Calculation steps
Step 1
Gregorian birth and reference dates; Umm al-Qura selected
Step 2
The Islamic calendar contains twelve lunar months and averages about 354 days, roughly eleven days shorter than a Gregorian solar year. A person therefore completes Hijri years faster, and the numerical Hijri age gradually becomes higher than the Gregorian age over a lifetime.
Step 3
Umm al-Qura: Unicode islamic-umalqura calendar data, representing the Saudi convention. Islamic civil: Tabular calendar with fixed arithmetic leap-year and month-length rules. Direct Hijri input: Year, month, and day must resolve to a real date in the selected calendar. Completed age: The selected-calendar anniversary must have occurred by the reference date.
Step 4
Completed Umm al-Qura age, both Hijri dates, Gregorian dates, and next birthday. The primary result follows the selected Saudi calendar convention.
The selected convention controls the primary conversion and completed age; the alternate convention is calculated from the same Gregorian days for transparency.
| Assumption | How this page handles it |
|---|---|
| Umm al-Qura | Unicode islamic-umalqura calendar data, representing the Saudi convention. |
| Islamic civil | Tabular calendar with fixed arithmetic leap-year and month-length rules. |
| Direct Hijri input | Year, month, and day must resolve to a real date in the selected calendar. |
| Completed age | The selected-calendar anniversary must have occurred by the reference date. |
| Input | Output | Why it matters |
|---|---|---|
| Gregorian birth and reference dates; Umm al-Qura selected | Completed Umm al-Qura age, both Hijri dates, Gregorian dates, and next birthday | The primary result follows the selected Saudi calendar convention. |
| Hijri birth and reference dates; civil selected | The dates are validated, converted to Gregorian, and compared with Umm al-Qura | A day that does not exist in the selected month is rejected. |
| Birth and reference share the same selected Hijri month/day | The completed Hijri age increases on that date | Calendar anniversaries, not average-day division, determine completed age. |
Edge cases
Umm al-Qura, civil arithmetic, and observed calendars can assign adjacent Hijri dates to the same Gregorian day.
Direct Hijri input is validated against the selected calendar and an impossible date is not silently moved.
The direct Hijri input interface is intentionally limited to 1200–1700 AH; official historical records may use a different local convention.
Use the calendar and conversion method required by the issuing authority.
Use it to calculate completed age and anniversaries under the selected Umm al-Qura or tabular Islamic-civil calendar and compare the alternate convention.
Do not use a computed date where a court, religious authority, local moon-sighting body, or official document requires a different convention.
A Hijri year is about eleven days shorter, so more lunar anniversaries occur.
Yes. Choose Umm al-Qura before entering either Gregorian or Hijri dates.
Yes. Select Hijri input and enter year, month, and day for both dates.
Yes. Religious month starts may follow local or official crescent-sighting decisions.
It makes boundary differences visible and helps users choose the convention required for their context.
No. A religious or local authority may announce dates based on its own observation policy.
We use these sources to define the age-counting rule, official context, or life-stage assumptions used by this calculator.
Last updated: July 22, 2026
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