How to use it
- Choose the date of birth with the date picker or type it.
- Leave “Age on this date” as today, or change it to see an age on another day, such as a deadline or an event.
- Read the exact age, the totals in months, weeks and days, and the countdown to the next birthday.
How it works
The age is counted the way people count birthdays: first whole years, then whole months, then the remaining days. A month is counted when the same day number is reached in a later month. If that day does not exist (for example the 31st in a 30-day month), the last day of that month is used. So someone born on 31 January is one month older on 28 February in a common year.
People born on 29 February have a real birthday only in leap years. This calculator counts their birthday on 28 February in other years, which keeps the result consistent with the month rule above. Some laws and organisations use 1 March instead, so for legal questions check the rule that applies to you.
Totals are exact: total days is the number of days between the two dates, total weeks is that number divided by 7 with the remainder shown, and total months counts completed months only. All calculations use the calendar dates you enter, with no time of day and no time zones, so the results never shift by a day because of daylight-saving time.
Examples
Exact age today
Born on 15 June 1990, on 22 October 2026 a person is 36 years, 4 months and 7 days old: 13,278 days in total. The next birthday, 15 June 2027, is a Tuesday, 236 days away.
Age on a deadline
A competition requires entrants to be under 18 on 1 September. Put the birth date in the first field and 1 September in “Age on this date” to see the age on that exact day.
Leap-day birthday
Born on 29 February 2000, a person is shown as turning 25 on 28 February 2025, and the next birthday after that is 28 February 2026.
Frequently asked questions
How is a month counted when months have different lengths?
A month is complete when the same day number is reached in a later month, or the last day of a shorter month. From 31 January, one month is complete on 28 February (29 in a leap year), and the remaining days are counted from there.
When does someone born on 29 February get older in a non-leap year?
This calculator uses 28 February. Customs and laws differ: some countries use 1 March for legal age. The difference is only ever one day.
Does the time of birth or my time zone matter?
No. The calculator works with calendar dates only. “Today” is today's date on your device.
Can I calculate an age in the future?
Yes. Set “Age on this date” to any future date, for example to see how old you will be when a loan ends or on a planned trip.
Privacy
Dates of birth are processed only in your browser. They are not sent, stored or included in analytics.