About the age calculator
Your age is the time that has passed between your date of birth and a chosen date. The calculator counts whole years first, then whole months, then the remaining days, and also converts the same span into total months, weeks, days and hours.
Month ends are handled with care. If you were born on the 31st and a month is shorter, the month is counted as complete on that month's last day. People born on February 29 celebrate on February 28 in common years in this calculator.
Why enter a different "age at" date?
You can type any date to see how old someone was, or will be. That is handy for checking school cut-off dates, eligibility ages and anniversaries.
Formula
- Whole months = months from birth date to the chosen date (month ends clamped)
- Years = whole months ÷ 12, Months = whole months mod 12
- Days = days left after the last whole month
- Hours = total days × 24
Example
Born on June 15, 1990 and measured on March 1, 2024: 33 years, 8 months and 15 days, which is 12,313 days in total. The next birthday is June 15, 2024, in 106 days.