Hijri Age Calculator

About this calculator

This is a Hijri age calculator, not a date converter: type your Gregorian (everyday) birth date and it tells you how old you are in the Islamic (Hijri) lunar calendar — your age in Hijri years, months, and days — alongside your ordinary Gregorian age and a plain-English explanation of why the two numbers differ. The Hijri calendar is purely lunar: each of its twelve months, Muharram through Dhu al-Hijjah, tracks a cycle of the moon, so a Hijri year runs only about 354 days, roughly 11 days shorter than the 365-day solar Gregorian year. Those missing days add up. Because each Hijri year is shorter, more of them fit into your lifetime, so your Hijri age is always a little HIGHER than your Gregorian age — about 3% more. Put differently, a person who is 33 in Gregorian years is about 34 in Hijri years, and the gap widens by roughly one full Hijri year every 33 calendar years. The calculator measures your age as of today and updates automatically wherever you are.

How to read your results

The big number is your age in the Islamic (Hijri) calendar — full years, with the leftover months and days shown beside it. Directly underneath, for comparison, is your Gregorian age computed over the exact same span of days, plus the drift insight that says how many extra Hijri years you have accumulated. Both ages cover an identical number of real calendar days (your birth date counted up to today); they only disagree on how those days are sliced into "years", because a lunar Hijri year is shorter than a solar Gregorian one. Hijri years carry the suffix AH (Anno Hegirae, "in the year of the Hijra"), counted from the Prophet Muhammad’s migration to Medina in 622 CE. The page also shows your birth date and today written in the Hijri calendar, so you can see exactly which Hijri birthday you are between. Note the disclosure below the result: this tool uses the tabular (arithmetic) Hijri calendar, so right at a Hijri birthday boundary your age can read a day either side of a moon-sighting or Umm al-Qura figure.

How it's calculated

Why only one direction? This page takes a Gregorian birth date and reports a Hijri age — it does not invert a Hijri date back to a number. That is deliberate: across this calendar cluster the lunar/Intl calendars are treated as OUTPUT-only because Intl.DateTimeFormat exposes some calendars’ month and year as non-numeric NAMES rather than plain counts, so a numeric year/month/day INPUT cannot address those dates unambiguously and the engine cannot reliably invert them (see the note in multi-calendar-age and the intlToJDN helper in the shared calendar engine). Taking the always-numeric Gregorian birth date keeps the input unambiguous. The math reuses the same engine as the rest of the cluster. Your Gregorian birth date is first reduced to a Julian Day Number (JDN) — a continuous, calendar-independent day count — and so is today (computed at your local civil midnight). The engine then counts whole elapsed years, then months, then days in each target calendar: ageInCalendar(birthJDN, todayJDN, "islamic") for the Hijri age and ageInCalendar(birthJDN, todayJDN, "gregorian") for the comparison. The Hijri side uses the tabular (arithmetic) algorithm of the US Naval Observatory and Fourmilab — a 30-year cycle in which 11 years are leap years (the years where (year × 11 + 14) mod 30 is less than 11), anchored to 1 Muharram AH 1 = Friday 16 July 622 CE (Julian). The drift figure compares the mean tabular Hijri year (10631 ÷ 30 ≈ 354.37 days) with the mean Gregorian year (365.2425 days): a deficit of about 10.9 days per year, which is why the Hijri age outruns the Gregorian age by roughly 3%. "Today" is read only after the page loads, at local civil midnight in your time zone, so no build-time date is baked into the page.

Worked example

Someone born on 1 January 2000 (Gregorian), checked as of 3 June 2025.

Their Gregorian age is 25 years, 5 months, 2 days. Their Hijri age over the very same 9,285 days is 26 years, 2 months, 12 days — a whole year more, exactly the lunar-versus-solar drift this page explains. (Both figures come from the shared tabular-Islamic engine, which is itself cross-checked against the US Naval Observatory and Fourmilab algorithms.) The pattern holds at every age: someone born on 1 January 1992 is 33 in Gregorian years on the same date but already 34 in Hijri years.

Frequently asked questions

Why is my Islamic (Hijri) age higher than my normal (Gregorian) age?

Because a Hijri year is shorter. The Hijri calendar is lunar — twelve lunar months totalling about 354 days — while the Gregorian year is solar at about 365 days, an 11-day difference. Over a lifetime those shorter years accumulate, so more Hijri years fit into the same span of days. The result is that your Hijri age is always a bit higher than your Gregorian age — about 3% more, gaining roughly one extra Hijri year every 33 calendar years.

How is Islamic age counted?

Exactly like any age, but in lunar years: it is the number of complete Hijri years that have passed between your birth date and today, plus the leftover Hijri months and days. This calculator converts both your birth date and today to a Julian Day Number, then counts whole Hijri years, then months, then days between them — the same way it counts your Gregorian age, just against the shorter lunar year.

I am 33 in Gregorian years — what is my age in Hijri years?

About 34. Because the Hijri year is roughly 11 days shorter than the Gregorian year, your Hijri age runs ahead by about 3%. A 33-year-old is typically 34 in Hijri years, a 50-year-old is about 51–52, and the gap keeps widening — close to one extra Hijri year for every 33 Gregorian years. Enter your exact birth date above for the precise figure rather than the rule of thumb.

Could my Hijri age be off by a day?

Right at a Hijri birthday, yes. This tool uses the tabular (arithmetic) Islamic calendar, which fixes month lengths by a 30-year cycle and is fully deterministic. Calendars based on actual moon-sighting, and the Saudi Umm al-Qura calendar, instead depend on whether the new crescent is seen, which can fall a day — occasionally two — before or after the arithmetic date. So in the day or two around a Hijri birthday your age here may read one year either side of a moon-sighting figure. For everyday use the tabular result is an exact, reproducible reference; confirm religious dates with your local authority.

Sources

Reviewed by the YouCalc Team · Last reviewedJune 13, 2026

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