About this age calculator
An age calculator computes calendar-accurate age between two dates. That matters for forms, eligibility checks, party planning, astrology curiosities, and knowing exactly how many days you have lived.
Unlike simply subtracting years, this tool accounts for month lengths and leap years so the years/months/days breakdown is exact.
How to use
- Enter your date of birth.
- Optionally change the “as of” date (defaults to today).
- View exact age, total days, weeks, and days until your next birthday.
Formula
Age is calculated by walking calendar years, then months, then days between the birth date and the target date — borrowing days from the previous month when needed.
Worked examples
Example: Born 15 March 2000, as of 15 March 2026 → 26 years, 0 months, 0 days.
Tips
- For legal age (driving, voting), use the official cut-off date in your country.
- Time zones do not affect date-only age calculations.
Frequently asked questions
Does this age calculator count leap years?
Yes. It uses real calendar dates, so February 29 and varying month lengths are handled correctly.
Can I calculate age on a future or past date?
Yes. Change the “Age as of” field to any date after the birth date.