Find out exactly how old you are — or anyone else, on any date. Enter a birth date and the calculator returns age the way people actually say it, in years, months, and days, along with the total months, weeks, days, and hours lived, the day of the week you were born, and how long until your next birthday. It handles the awkward cases correctly: birthdays on the 31st, leap-day birthdays (with a February 28 or March 1 choice), and very old or future dates.
Everything runs in your browser, so the dates you type never leave your device. To measure the gap between any two moments rather than an age, use the duration calculator; to count down to a birthday or event in real time, try the countdown timer; and to turn a date into a Unix timestamp, the timestamp converter has you covered. Age also feeds your health numbers: the calorie calculator uses it in its energy formula, and the BMI calculator explains why a child's BMI is read against age percentiles.
Frequently asked questions
How is exact age in years, months, and days calculated?
The calculator adds whole years and then whole months to your birth date for as long as the result does not pass the "as of" date, then counts the days that are left over. That is how people naturally state age: someone born on May 15, 1990 is 36 years, 4 months, and 15 days old on September 30, 2026. Because it steps through real calendar months instead of dividing by an average month length, the answer never drifts by a day and none of the parts is ever negative.
What happens if I was born on the 29th, 30th, or 31st?
Some months are shorter than your birth day, so the calculator uses the last day of the month instead. If you were born on January 31, you complete a month on February 28 (or 29 in a leap year), then March 31, April 30, and so on. This end-of-month rule is the same one spreadsheets and most date libraries use, and it guarantees the months-and-days answer adds up exactly to your real calendar age. Birthdays on the 29th and 30th follow the same rule in February.
I was born on February 29. When is my birthday in other years?
In leap years it is February 29. In the other three years, there are two common conventions, and the calculator lets you pick. February 28 keeps the celebration in your birth month and is what most people choose. March 1 is the day that follows February 28, and it is the legal date you turn a year older in some countries, including the United Kingdom and New Zealand. The toggle changes both your next-birthday date and the exact day your age ticks over.
Why add a birth time?
Without a time, the calculator counts whole calendar days, so on your birthday you are a full year older from midnight. With a birth time, the last day only counts once that clock time has passed, and you also get hours and minutes plus an exact total of hours lived. Times are treated as wall-clock times in one place — time zone changes and daylight-saving shifts between your birth and today are not applied, which can move the hour count by one or two.
Can I calculate age on a past or future date?
Yes. Change the "Age as of" date to any day — for example, to check how old someone was on a historical date, whether a child will meet a school-entry cutoff next September, or how old you will be at retirement. The total days, weeks, and next-birthday countdown are all measured from that date. Press Today to return to the current date. Dates from year 1 to 9999 are supported using the modern (Gregorian) calendar throughout. Add a birth time as well for an answer down to the hour and minute.