Date & Time
Hijri Age Calculator
Your age on the Islamic lunar calendar — always a little higher than your Gregorian age, because a lunar year is 11 days shorter.
Hijri Age Calculator
Hijri dates here use the tabular (arithmetical) Islamic calendar, which is fixed and predictable. Locally observed dates depend on moon sighting and can differ by a day either way — check with your local authority for religious observances.
About the Hijri Age Calculator
Enter your Gregorian date of birth and this calculator gives your age on the Islamic lunar calendar — in Hijri years, months and days. Your Gregorian age is shown next to it so you can see the gap.
That gap always runs the same way: your Hijri age is higher. A lunar year is roughly eleven days shorter than a solar one, so you accumulate Hijri birthdays slightly faster. The difference is about one extra year for every 33 years you live.
You also get the Hijri date of your birth and the date of your next Hijri birthday, both in the tabular calendar and with the Gregorian equivalent alongside.
How to use the Hijri Age Calculator
- Pick your Gregorian date of birth.
- Select Calculate Hijri age.
- Compare the Hijri and Gregorian ages — the gap grows as you get older.
- Your Hijri birth date is shown so you can note the anniversary.
- The countdown is to your next Hijri birthday, not your Gregorian one.
Why a Hijri age is always higher
The two calendars measure different things. A Gregorian year tracks the Earth’s orbit around the sun at 365.2425 days. A tabular Hijri year averages 354.367 days, following twelve lunar months.
Gregorian year ≈ 365.2425 days
Hijri year ≈ 354.3667 days
Difference ≈ 10.88 days per year
Those eleven days accumulate. After about 33 solar years you have lived through roughly 34 lunar ones, which is where the familiar rule of thumb comes from.
Worked example
Born 15 March 1990, measured on 6 September 2026 — 13,324 days.
Gregorian: 13,324 ÷ 365.2425 = 36.5 years.
Hijri: 13,324 ÷ 354.3667 = 37.6 years.
36 Gregorian years — 37 Hijri years — just over one year apart
How the gap grows with age
| Gregorian age | Approx. Hijri age | Difference |
|---|---|---|
| 10 | 10 | +0 (about 4 months) |
| 20 | 20 | +0 (about 7 months) |
| 33 | 34 | +1 year |
| 40 | 41 | +1 year |
| 50 | 51 | +1 year |
| 66 | 68 | +2 years |
| 80 | 82 | +2 years |
| 99 | 102 | +3 years |
The rule is simple: add roughly three years per century of life, or one year for every 33. Someone who reaches 99 Gregorian years has lived 102 Hijri ones.
Your Hijri birthday moves through the Gregorian year
Because the lunar year is shorter, your Hijri birthday arrives about eleven days earlier in the Gregorian calendar each year. Over roughly 33 years it works its way backwards through every season and returns to where it started.
So a Hijri birthday that falls in June this decade will fall in the spring a decade later, then in winter, then autumn. If you were born in Ramadan, your Hijri birthday stays in Ramadan every year — but the Gregorian date of that birthday keeps shifting.
Where a Hijri age is used
- Official documents in Saudi Arabia and some other states, where the Hijri calendar is the civil standard.
- Religious milestones such as the age of obligation for fasting and prayer, which are reckoned in lunar years.
- Zakat — the hawl, the qualifying period of holding wealth, is one full lunar year rather than a solar one.
- Family records where births were originally recorded on the Islamic calendar.
Zakat’s lunar year matters more than it first appears: a lunar year is eleven days shorter, so obligations recur slightly more often than an annual solar cycle would suggest. Our Zakat calculator covers the calculation itself.
Why your local calendar might differ by a day
This calculator uses the tabular Islamic calendar, which is arithmetic and fixed. Locally observed dates depend on sighting the new crescent moon, and that varies with weather, geography and the criteria each country applies.
Expect agreement with your local calendar most of the time and a ±1 day difference some of the time. For anything official or religious, use the date your local authority publishes. For the underlying date conversion, see the Gregorian to Hijri converter.
Find your Hijri birthday
Enter your Gregorian date of birth. The result shows your Hijri date of birth and your next Hijri birthday, with a countdown.
Your Hijri birthday comes about 11 days earlier each Gregorian year. Over roughly 33 years it travels through every season and lands back near where it started.
| Gregorian age | Approx. Hijri age | Extra Hijri years |
|---|---|---|
| 10 | 10.3 | 0.3 |
| 20 | 20.6 | 0.6 |
| 33 | 34.0 | 1.0 |
| 50 | 51.5 | 1.5 |
| 66 | 68.0 | 2.0 |
A simple rule: you gain one extra Hijri year for about every 33 Gregorian years.
Using a Hijri calendar calculator for other dates
This page is built for age. For other jobs, use the matching tool:
- Convert any single date either way — Gregorian to Hijri converter.
- Count the days or months between two Islamic dates — Hijri date difference calculator.
- Check your Gregorian age to the day — age calculator.
Other ways to use this calculator
- Islamic age calculator and Muslim age calculator — your age counted in Hijri years.
- Lunar age, Islamic calendar age and Hijri calendar age calculator — Hijri years are about 11 days shorter, so your lunar age is higher.
- Hijri birthday calculator — see the section above to find your next Hijri birthday.
Frequently asked questions
Because a lunar year is shorter than a solar one — about 354.37 days against 365.24, a difference of nearly eleven days. You therefore pass Hijri birthdays slightly faster than Gregorian ones. The gap accumulates at roughly one extra year for every 33 lived, or about three years per century. At 40 Gregorian you are around 41 Hijri; at 80, about 82.
A tabular Hijri year is 354 days, or 355 in a leap year, averaging 354.367 days across the 30-year cycle. That is twelve lunar months, each following the moon’s phases and running 29 or 30 days. It is about eleven days shorter than the Gregorian year, which is why Islamic dates move backwards through the seasons rather than staying fixed.
It is the same Hijri month and day each year, but it lands on a different Gregorian date — roughly eleven days earlier each time. Enter your birth date above and the calculator gives your next Hijri birthday in both calendars. Over about 33 years the Gregorian date travels backwards through every season and returns to where it began.
This tool uses the tabular Islamic calendar, which is calculated from a fixed 30-year arithmetic cycle. Locally observed calendars set each month by sighting the new crescent moon, which depends on weather, geography and the criteria your country applies. A ±1 day difference is normal. For anything official or religious, follow the date your local authority announces.
Enter your Gregorian date of birth. The calculator converts it to the Hijri calendar and shows your next Hijri birthday with a countdown. It arrives about 11 days earlier each Gregorian year.
Sources and further reading
- HM Nautical Almanac Office — Islamic calendar and crescent visibility — the tabular calendar and observed-date variation
- Islamic calendar — Encyclopaedia Britannica — lunar year length and calendar structure
- US Naval Observatory — Julian date converter — the day-count system underlying the conversion