Age Calculator
Exact age in years, months and days.
Exact age in years, months and days.
Most people know their age without thinking, but exact calculations matter on forms, applications, insurance, school admissions and legal documents. Age is the length of time since you were born, usually shown in full years, and sometimes in years, months and days. This guide explains how the calculation works, why dates near the end of a month can be tricky, and how different calendars and countries count age. You can check any date with the calculator above.
To calculate age in years, subtract your birth year from the current year. Then check whether your birthday has already happened this year. If it has not, subtract one. For exact months and days, count the full years first, then count the full months since your last birthday, and then the remaining days. Someone born on 15 March 2000 is, on 10 November 2026, 26 years, 7 months and 26 days old. That is 26 full years up to 15 March 2026, 7 full months up to 15 October, and the remaining days up to 10 November.
The harder cases happen when the current day of the month is smaller than the birth day. If you were born on 28 January and today is 5 March, you cannot simply subtract 5 from 28. Instead you borrow the number of days in the previous month. February has 28 days in most years, so the count is 5 plus 28 minus 28, which gives 5 days, and one month is taken away from the month count. A good calculator does this automatically and uses the correct length of each month, including February in leap years.
A leap year has 366 days, with an extra day on 29 February. A year is a leap year if it divides by four, except century years, which must divide by 400. This is why 2000 was a leap year but 1900 was not. People born on 29 February have an official birthday only every four years. In common practice they celebrate on 28 February or 1 March in other years, and the legal date can differ between countries. If a form depends on the exact date, check the local rule.
Besides years and months, many people enjoy knowing how many days they have lived. The calculator shows an approximate total in days. As a guide, 10,000 days is about 27 years and 4 months. One billion seconds is about 31.7 years. These milestones are fun to mark, and some people celebrate them like a second birthday. Remember that the number of days depends on how many leap days fall between the two dates.
The Gregorian calendar is based on the Earth's journey around the sun. The Islamic Hijri calendar is based on the moon and has a year of about 354 or 355 days. Because a lunar year is roughly ten or eleven days shorter, a person's age in Hijri years grows slightly faster. After about 33 lunar years, a person has lived roughly 32 solar years. If an official document or an application asks for your Hijri age, you need a Hijri date converter. This calculator uses the Gregorian calendar.
Not every country counts age the same way. In many places a baby is zero years old at birth and gains a year on each birthday, which is the method used by this calculator. Traditional East Asian systems counted a baby as one year old at birth and added a year at the start of the new calendar year. South Korea officially moved to the international method in 2023 for most legal and administrative purposes, though older habits remain in some everyday situations. Always check which system a form is using.
If you were born close to midnight, or if you now live in a different time zone from your birthplace, the date on a document may not match the date in your current location. For legal purposes, the date recorded on the birth certificate is normally the one that counts. For fun calculations like total days, the difference is only a few hours and does not change the result in a noticeable way.
People most often make errors by subtracting years only, forgetting whether the birthday has passed, miscounting months with 30 or 31 days, ignoring leap years, and entering the date in the wrong order. Date formats differ between countries, so 03/04/2000 could mean 3 April or 4 March. The date picker in the calculator avoids this problem, but be careful when you type dates elsewhere.
Pick your date of birth. The tool shows your exact age in years, months and days, plus the approximate number of days you have lived. The calculation uses the date on your device and runs in your browser, so your birth date is not stored or sent anywhere. If the date is in the future, the tool asks for a valid past date.
How old am I in months? Multiply your full years by 12 and add the extra months shown.
Why is my age different on another website? Sites may use different time zones or count the current day differently.
Can I calculate someone else's age? Yes. Enter their date of birth. Nothing is saved.
Does the calculator work for Hijri dates? No. Use a Hijri converter first and enter the Gregorian date.