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Age Calculator

Enter a date of birth to get exact age in years, months and days, plus total days lived, the weekday of birth and the countdown to your next birthday.

By Adzita Editorial Team · Updated 2026-11-03 · How we build and check our tools

What makes this page different: This tool lets you calculate age at any date (not only today), shows the weekday of birth and days to your next birthday, and states how it handles leap-day birthdays instead of leaving you to guess.

How age is calculated

The calculator counts whole months from the date of birth, then counts the leftover days. If the day of the month has not yet been reached, the last month is not counted. For example, someone born on 15 May 1990 is, on 1 November 2026, 36 years, 5 months and 17 days old.

Leap years and 29 February

People born on 29 February have a real birthday only every four years. Rules differ between countries. This tool counts the birthday on 1 March in non-leap years. Check the rule that applies to your legal or administrative purpose.

Common uses

Use the second date field to find age at a past or future date, for example a cut-off date for an application.

Medical disclaimer: This tool is for education and general planning. It is not medical advice and does not diagnose any condition. If you are pregnant, under 18, have an eating-disorder history or a medical condition, speak to a doctor or registered dietitian before changing your diet or exercise.

Frequently asked questions

How do I calculate my age in days?

Subtract the date of birth from today. The calculator does it automatically and shows total days lived.

How is age calculated for a leap-day birthday?

This tool counts the birthday on 1 March in non-leap years. Some jurisdictions use 28 February.

Can I find age on a specific date?

Yes. Change the "Age at date" field to any date after the date of birth.

Does the time zone matter?

Dates are compared as calendar dates, so time zones do not change the result.

Why do some countries count age differently?

Some East Asian traditions count a person as one year old at birth. This tool uses the international standard.

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