If you have ever filled in a Saudi government form, you may have been asked for your age or date of birth in the Hijri calendar. And if you tried to work it out, you probably noticed something odd: your Hijri age is higher than your Gregorian one.
Why the numbers differ
A Hijri year follows twelve lunar months and lasts about 354 days. A Gregorian year lasts about 365.24 days. Because Hijri years are roughly 11 days shorter, you complete them faster. After about 33 years the gap adds up to a full extra year.
| Gregorian age | Approximate Hijri age |
|---|---|
| 18 | 18 and a half |
| 30 | about 31 |
| 45 | about 46 |
| 60 | about 62 |
The quick estimate
This gives you a decent ballpark. For anything official, you need the exact figure, because being a few days either side of a birthday can matter.
The exact method
- Convert your date of birth to the Hijri calendar, using Umm al-Qura if the form is Saudi.
- Convert today’s date (or the reference date on the form) to Hijri as well.
- Subtract year from year, month from month and day from day, borrowing a month when needed. Remember that Hijri months have 29 or 30 days, so the borrowed month length changes.
An age calculator does all three steps at once and also shows the result in Gregorian years for comparison.
When it matters
- Age limits written in Hijri dates in some Saudi regulations and forms.
- Calculating eligibility dates such as retirement or programme entry where rules specify the Hijri calendar.
- Personal milestones some families mark by the Hijri calendar.
Always check which calendar the organisation uses before you submit, as rules differ between institutions and countries.
A full example with real dates
Take someone born on 10 March 1995 and work out their age on 16 October 2026.
- Gregorian age: 31 years, 7 months and 6 days.
- Days lived: 11,543 days between the two dates.
- Hijri years: 11,543 ÷ 354.37 (the average Hijri year) ≈ 32.6 Hijri years.
So the same person is 31 in Gregorian years but already past 32 in Hijri years. The gap grows by about one year for every 33 years of life, because each Hijri year is roughly 11 days shorter.
Quick reference table
| Gregorian age | Approximate Hijri age |
|---|---|
| 10 | 10 years, 3–4 months |
| 18 | 18 years, about 7 months |
| 30 | almost 31 |
| 40 | 41 years, 2–3 months |
| 60 | 61 years, about 10 months |
These are estimates. For an exact answer you need the full birth date and an agreed calendar, usually Umm al-Qura in Saudi Arabia, which is what the age calculator uses.
Why your Hijri birthday moves every year
If you were born on 1 Ramadan, your Hijri birthday falls on 1 Ramadan every year, but that day lands about 11 days earlier on the Gregorian calendar each time. Over roughly 33 years it travels through every season. The same is true for Ramadan, Eid and Hajj, which is why they arrive in summer for some years and in winter for others.
Common mistakes
- Subtracting years only. If your birthday has not happened yet this year, you are one year younger than the subtraction says. The same applies in Hijri years.
- Mixing calendars. Never subtract a Hijri year from a Gregorian one. Convert both dates to the same calendar first.
- Using 365 days for a Hijri year. Hijri months have 29 or 30 days, and a year has 354 or 355 days.
Frequently asked questions
Why is my Hijri age higher?
Because a lunar year is about 354 days long, so more Hijri years fit into the same stretch of time than Gregorian years.
Can two converters disagree by a day?
Yes. Some use astronomical calculation and others the Umm al-Qura calendar, and the start of a month can differ by a day. Your age in years is very rarely affected.
Which age do official forms ask for?
It depends on the authority. Saudi government services moved most civil matters to the Gregorian calendar, but older documents and some forms still use Hijri dates, so read the requirement carefully.