Age Calculator

Enter a date of birth to get an exact age in years, months, and days. The age calculator also counts total days lived and the days until the next birthday.

Updated
Runs in your browser. Your data is not uploaded.

Age
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How to use the Age Calculator

  1. Enter the Date of birth.
  2. Leave Age on set to today, or change it to find the age on another date.
  3. Press Calculate. The age appears in years, months, and days, followed by total months, weeks, and days, the next birthday, and the weekday of birth.

How it works

The calculator counts whole months forward from the date of birth to the "age on" date. When a month is shorter than the birth day (for example, a birthday on the 31st), the day is moved to the last day of that month. The days left over after the last whole month are the days in the result.

years = whole months ÷ 12   (rounded down)
months = whole months − years × 12
days = days after the last whole month

Total days is the plain count of days between the two dates. For a February 29 birthday, the birthday in a non-leap year is taken as February 28.

Examples

  • Born 1990-05-15, age on 2026-09-25: 36 years, 4 months, 10 days. That is 13,282 days in total. The next birthday is Saturday, May 15, 2027, in 232 days.
  • Born 2000-02-29, age on 2025-02-28: 25 years, 0 months, 0 days. On 2025-02-27 the result is 24 years, 11 months, 29 days.

How age is counted

Age is counted in completed years. You turn 36 on your 36th birthday, not partway through the year before. The months and days in the result show how far you are into your current year of age.

Months have different lengths, so an age in months and days depends on which months fall in between. The calculator counts real calendar months from the birth date, the same way you would count on a calendar by hand.

Common uses

  • Checking an age requirement on a specific date, such as for school entry or retirement
  • Finding a baby's age in months
  • Counting down the days to a birthday
  • Finding the weekday someone was born

Limitations

  • A date of birth after the "age on" date gives an error.
  • February 29 birthdays are counted as February 28 in non-leap years. Some countries use March 1 for legal purposes, so check the rule where you live.
  • Dates before the year 1000 are not supported.
  • Your date of birth is never put in the page address or sent to analytics.

Frequently asked questions

How is my exact age calculated?

The calculator counts the whole years and months since your birth date, then the days left over. It follows the real length of each month and leap years.

How is a February 29 birthday handled?

In years without February 29, your birthday is counted as February 28. Some countries use March 1 instead, so check the rule that applies to you for legal purposes.

Can I calculate my age on a future date?

Yes. Change the "Age on" date to any date after your birth date.

Is my date of birth stored?

No. The calculation runs in your browser, and your date of birth is not sent anywhere.

Often used together with the Age Calculator.