Age Calculator
Exact age in years, months and days, with totals in months, weeks and days and the next birthday.
Dates
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How the age calculator works
Your age is the time between your date of birth and a second date, usually today. The calculator finds the number of whole years and months that have passed, then the remaining days, and also shows the total in months, weeks and days.
It also works out your next birthday, how many days away it is and how old you will be, and the day of the week you were born on.
Worked example
Someone born on May 15, 1990 wants their age on November 9, 2026.
- Whole years: May 15, 1990 to May 15, 2026 is 36 years.
- Whole months: May 15 to October 15, 2026 is 5 more months.
- Remaining days: October 15 to November 9 is 25 days.
- Age: 36 years, 5 months and 25 days, or 13,327 days in total.
- Next birthday: May 15, 2027, in 187 days, when they turn 37.
Assumptions and limitations
- Age is counted in completed years, the usual convention in English-speaking countries.
- Dates use the Gregorian calendar and the date on your device. Times of birth are not taken into account.
- For 29 February births, the birthday falls on 28 February in non-leap years, as explained above.
- For legal or official purposes, check the rules of the organisation that needs your age.
Frequently asked questions
How is age in months and days worked out?
The calculator counts whole months from the date of birth to the chosen date, as long as the same day of the month has been reached, then counts the days left over. Twelve whole months make a year.
When is the birthday of someone born on 29 February?
In years without a 29 February, this calculator counts the birthday on 28 February. Rules for legal purposes differ between countries, and some use 1 March, so check the rule that applies to you if it matters.
Can I find out my age on a past or future date?
Yes. Change the “Age on” date. This is useful for questions like how old someone will be on a certain date, or how old they were at an event.
Why is the number of days not just years × 365?
Leap years add an extra day roughly every four years, and the calculator counts the actual calendar days between the two dates.
Is my date of birth stored anywhere?
No. The calculation happens in your browser and the dates you enter are not sent to a server.