Everyday Tools
Age Calculator
Calculate calendar age on a chosen reference date and the next anniversary.
✓ Free
✓ No account
◉ Runs on this device
Everyday Tools
Powering up the tool…
TOOL AGE-CALCULAT
What this tool does
About the age calculator
The result uses date-only calendar arithmetic to avoid time-zone drift and explains leap-day handling. It is a convenience calculation, not identity verification.
How to use it
- Enter the birth date and the reference date (today is the default).
- Read the exact age in years, months and days.
- Check the next-anniversary countdown.
- For 29 February birthdays, pick how the anniversary lands in ordinary years.
Useful for
- Work out someone’s exact age on a specific date for a form.
- Find how long until the next birthday or anniversary.
- Calculate an age as of a past reference date — “how old were they when…”.
Straight answers
Age Calculator FAQ
How do leap-day birthdays work?
Born 29 February, your calendar birthday exists once every four years; jurisdictions and personal preference split between 28 February and 1 March in other years. The tool lets you choose and applies it consistently, rather than deciding for you.
Why date-only arithmetic?
Because ages are a calendar concept. Mixing in clock time and time zones can shift a birthday across midnight and produce off-by-one ages — the exact bug this method avoids.