Free Age Calculator
The Age Calculator works out your exact age from a birth date in years, months, and days, plus the total days lived and the next birthday countdown.
How to use the Age Calculator
- 1 Enter your date of birth.
- 2 Optionally set the date to calculate against — it defaults to today.
- 3 Read your age in years, months and days, plus the total in days, weeks and hours.
- 4 Use the next-birthday readout to see how many days remain and which weekday it falls on.
How to Use
Pick your date of birth (and optionally a "as of" date, defaulting to today). The result updates instantly.
- Exact age in years, months, days
- Total days, weeks, and hours lived
- Days until next birthday
Frequently asked questions
How is age in years actually calculated?
By counting completed anniversaries, not by dividing days by 365. Someone born on 1 March 2000 is 25 on 1 March 2025 and still 24 on 28 February 2025, even though 9,130 days have passed.
Why does my age in days differ from age × 365?
Because of leap years. Multiplying years by 365 ignores the extra day every fourth year, which adds up to roughly 25 days by age 100. Counting actual calendar days avoids that drift.
How do I calculate age for a legal or official form?
Use the completed-anniversary method, which is the standard legal definition in most jurisdictions. This tool reports it as the years/months/days figure at the top of the results.
Related Calculators
You might also need
Tools from other categories that people pair with the Age Calculator: