# Hijri Age Calculator — Your Age in 8 Calendars > Find your exact age in the Islamic (Hijri), Gregorian, Hebrew, Persian, Julian, Saka, Ethiopian and Chinese calendars, and convert any date between all 8. - **Category:** Date & Time - **Interactive calculator:** https://youcalc.com/en/date-time/multi-calendar-age/ - **Price:** Free, no sign-up required ## Overview This calculator shows your exact age simultaneously in eight calendars — Gregorian, Julian, Islamic (Hijri), Hebrew, Persian (Jalali), Indian (Saka), Ethiopian and Chinese — and explains in plain language why your Hijri age comes out higher than your Gregorian age. Enter your birth date in whichever calendar you know it in, choose an "as-of" date (today by default), and read your age across every system at once. A second mode converts any single date between all eight calendars. It is built for anyone who needs both their Hijri and Gregorian age, students of comparative calendars, and genealogists reconciling dates written in different systems. ## How to read your result The headline figure is your age in the Islamic (Hijri) calendar, the calendar this tool leads with. The table below lists your age in all eight calendars side by side. For the Gregorian, Julian and Hijri calendars you get a full years-months-days breakdown; for the Hebrew, Persian, Saka, Ethiopian and Chinese calendars you get the number of completed years plus the exact total days you have lived. The total-days column is identical in every row — that is the same span of time, just grouped differently by each calendar. The note beneath the table explains the Hijri drift: because the lunar year is about 11 days shorter than the solar year, the Hijri count of years runs ahead and the gap grows by roughly one year every 33 years. ## Method Every date is reduced to a Julian Day Number (JDN), a continuous integer count of days since a fixed epoch, and every output is derived from that single pivot. The Gregorian, Julian and tabular Islamic conversions are hand-rolled from the standard algorithms (Fourmilab / US Naval Observatory): the Gregorian and Julian use the classic civil-date formulas, and the tabular Hijri uses the 30-year cycle with 11 leap years and the leap rule ((year × 11) + 14) mod 30 < 11, anchored to the epoch JDN 1948439.5 (1 Muharram AH 1 = Friday 16 July 622 CE in the Julian calendar). The Hebrew, Persian, Indian (Saka), Ethiopian and Chinese calendars are read through Intl.DateTimeFormat's ICU calendars at the civil noon of each JDN, which yields an exact year and day; the total days lived is simply the difference of the two JDNs, so it is identical across calendars. Age in years is computed by counting completed calendar-year anniversaries up to the as-of date, clamping to the last valid day when a birthday lands on a date that does not exist that year (such as 29 February). The Hijri-drift figure compares the mean tabular Hijri year (10631 ÷ 30 ≈ 354.367 days) with the mean Gregorian year (365.2425 days), a deficit of about 10.876 days per year, and reports the approximate extra Hijri years your age accumulates. "Today" is computed at local civil midnight in your time zone, after the page mounts, so the default as-of date is correct wherever you are without baking a build-time date into the page. ## Example - **Setup:** Born 1 January 2000 (Gregorian), age measured as of 3 June 2025. - **Result:** Gregorian age 25 years 5 months 2 days; Hijri age 26 years 2 months 12 days — the same 9,285 days lived, but the Hijri calendar counts one extra completed year because its lunar year is shorter. The birth date itself converts to 24 Ramadan 1420 AH and 11 Dey 1378 in the Persian calendar. ## Frequently asked questions ### Why is my Hijri (Islamic) age higher than my Gregorian age? The Hijri year is lunar and about 11 days shorter than the solar Gregorian year (roughly 354.4 days versus 365.2). Those shorter years accumulate, so the number of completed Hijri years runs ahead of your Gregorian age, gaining about one extra year every 33 years. ### Is the Hijri date this calculator shows exact? It uses the tabular (arithmetic) Islamic calendar, which is fully deterministic and the standard choice for date arithmetic. The date observed by actual moon-sighting, and the Saudi Umm al-Qura calendar, can differ from the tabular date by one day, and occasionally two, because they depend on the visibility of the new crescent moon. Treat the tabular date as an exact calculated reference, not a religious moon-sighting ruling. ### Why do some calendars show only years and total days, not months and days? The Gregorian, Julian and tabular-Hijri calendars are computed from explicit formulas, so a full year-month-day age is available. The Hebrew, Persian, Saka, Ethiopian and Chinese calendars are resolved through your system's international calendar support, which gives an accurate year and the exact total days but not a reliable months-and-days split — so those are shown as years plus total days. ### Can I enter my birth date in a non-Gregorian calendar? Yes. Choose the source calendar your date is written in — for example Hijri or Persian — and enter the year, month and day in that calendar. The calculator converts it to the underlying day count and reports your age in all eight calendars from there. ### What is the "Convert a date" mode for? It takes a single date in one calendar and shows the equivalent date in all eight, with no age involved. It is useful for reading a historical or religious date written in one system and finding its Gregorian equivalent, or vice versa. ## Related calculators - [Ramadan Fasting Hours Calculator](https://youcalc.com/en/date-time/ramadan-fasting-hours/) - [Zakat Calculator](https://youcalc.com/en/finance-money/zakat/) - [Business Days Calculator](https://youcalc.com/en/date-time/working-days-counter/) - [Anniversary Countdown Calculator](https://youcalc.com/en/date-time/anniversary-countdown/) ## Sources - https://aa.usno.navy.mil/faq/islamic - https://www.fourmilab.ch/documents/calendar/ - https://en.wikipedia.org/wiki/Tabular_Islamic_calendar --- Interactive version: https://youcalc.com/en/date-time/multi-calendar-age/ · From YouCalc — https://youcalc.com