Age Calculator

Age calculator in both the Hijri and Gregorian calendars

Knowing your age precisely is something people need in many situations, from filling in official forms to knowing whether they have reached an age on which religious rulings or legal rights depend. This calculator lets you find your age in years, months and days in both the Gregorian and Hijri calendars, as well as the total number of days you have lived and the date of your next birthday. On this page we explain the calculation method, why age differs between the two calendars, and the most important practical uses of each.

How is age calculated?

In its simplest form, calculating age means subtracting the date of birth from the current date, but accuracy requires taking into account that months are not of equal length. The calculator follows these steps:

1. Calculating the full years: by subtracting the year of birth from the current year, then subtracting one year if the birthday has not yet arrived in the current year.
2. Calculating the remaining months: by counting the full months that have passed since the last birthday.
3. Calculating the days: by counting the days remaining after the last full month, taking into account the number of days in the previous month (28, 29, 30 or 31 in the Gregorian calendar, and 29 or 30 in the Hijri calendar).

In the Gregorian calendar, the calculator takes into account leap years, in which February has 29 days. In the Hijri calendar, the date of birth is first converted to its Hijri equivalent according to the Umm al-Qura calendar, and then the same calculation is applied to the lunar months. You can convert any single date using the Hijri date converter.

Why is your age in Hijri years greater than in Gregorian years?

Many people notice that their age in the Hijri calendar is greater than their Gregorian age. The reason is that the lunar Hijri year is about 11 days shorter than the solar Gregorian year: the Hijri year is 354 or 355 days, while the Gregorian year is 365 or 366 days. So if a person has lived a certain number of days, the number of lunar years those days contain is greater than the number of solar years.

The difference is roughly 3%, which equals one extra Hijri year approximately every 33 Gregorian years. Someone who is 33 Gregorian years old is about 34 Hijri years old, and someone who is 66 Gregorian years old is close to 68 Hijri years old. The Holy Quran alluded to this difference between the two reckonings in the story of the People of the Cave, according to many exegetes:

﴿وَلَبِثُوا فِي كَهْفِهِمْ ثَلَاثَ مِائَةٍ سِنِينَ وَازْدَادُوا تِسْعًا﴾“And they remained in their cave for three hundred years and exceeded by nine.”Surah Al-Kahf: 25

A number of exegetes mentioned that three hundred solar years are equivalent to three hundred and nine lunar years, which agrees with the ratio mentioned above.

Uses of calculating age in Hijri and Gregorian

Puberty and religious accountability

Puberty (bulugh) is the basis of religious accountability for prayer, fasting and all other obligations. It has well-known natural signs, and if they do not appear, age is what counts. The jurists differed in determining the age of puberty in the absence of signs: the majority held that it is fifteen years, while others held it to be a later age. What is meant in their statements is Hijri years, as this is the religiously recognised calendar, which is why knowing your Hijri age is useful for anyone who wants to apply this ruling precisely. It is stated in the hadith:

"The pen has been lifted from three: from the sleeper until he wakes, from the child until he reaches puberty, and from the insane until he regains his reason."Narrated by Abu Dawud

Hajj and permit systems

Hajj is obligatory once in a lifetime for every adult Muslim who is able, as Allah the Exalted said:

﴿وَلِلَّهِ عَلَى النَّاسِ حِجُّ الْبَيْتِ مَنِ اسْتَطَاعَ إِلَيْهِ سَبِيلًا﴾“And [due] to Allah from the people is a pilgrimage to the House — for whoever is able to find thereto a way.”Surah Al 'Imran: 97

The authorities organising Hajj in some countries may set age-related conditions for registration or priority, so applicants need to know their age precisely according to the calendar adopted by that authority.

Official documents

Some countries use the Hijri calendar in official documents or mention it alongside the Gregorian one, so the Hijri age may be requested on identity, passport or education forms, and some statutory periods may be calculated with it. It is therefore useful to know your age in both calendars to avoid errors when filling in forms.

Retirement and employment periods

In systems that calculated the retirement age or length of service by the Hijri calendar, an employee reaches the statutory age about two years before the Gregorian date at the age of sixty, because of the accumulated difference between the two calendars. Some countries have changed their systems to the Gregorian calendar, so you should refer to the system applied in your country and at your workplace.

How to use the age calculator

1. Choose the type of date of birth you know: Gregorian or Hijri.
2. Enter the day, month and year of birth.
3. Today's date is used automatically for the calculation, and you can change it to another date to find your age on a specific day in the past or future.
4. Press the calculate button to show the results: the Gregorian age, the Hijri age, the total days, weeks and months, and the time remaining until your next birthday.

Worked example

Suppose a person was born on 15 March 1990 and wants to know their age on 1 October 2026:

• Years: 2026 − 1990 = 36 years, and since 15 March has already passed in 2026, the full years are 36.
• Months: from 15 March 2026 to 15 September 2026 is six full months.
• Days: from 15 September to 1 October is 16 days, because September has 30 days.

So their Gregorian age is 36 years, 6 months and 16 days. The total number of days is about 13,349; dividing it by the average lunar year (about 354.37 days) gives roughly 37 Hijri years and eight months, meaning their Hijri age exceeds their Gregorian age by more than a year, which is consistent with the rule of one extra year every 33 years. The calculator shows the Hijri result in detail in years, months and days based on the actual Hijri date corresponding to each of the two dates.

Tips for an accurate result

• Make sure you enter your date of birth exactly as it is recorded in your official documents.
• If your date of birth is recorded in Hijri, enter it directly in Hijri rather than converting it manually, to avoid conversion differences.
• Remember that the conversion relies on the Umm al-Qura calendar and may differ by one day from other local calendars.

For more useful tools, try Prayer Times and Islamic Events, or browse the articles.