Age Calculator
Calculate exact age in years, months, days, hours, and minutes. Find next birthday and day of week you were born.
Runs entirely in your browser. Nothing is sent to our servers.
About this tool
Calculates exact age from birth date. Shows years/months/days, total days lived, the day of the week you were born, and your next birthday. Also works for calculating age at a past or future date — useful for legal forms, school registration, or just curiosity.
What it shows
- Years, months, and days — your "official" age.
- Total days lived — the running counter that birthday-card people love.
- Day of the week you were born — surprisingly hard to remember without a calendar.
- Next birthday — date, day of the week, and how far away.
- Hours, minutes, seconds — for the curious.
Edge cases
Leap-year birthdays (February 29) work correctly — in non-leap years your "next birthday" rolls to March 1. If you set the "calculate on" date before the birth date, you'll get a negative age (someone not yet born).
Frequently asked questions
- Why does my "months" not match what I expected?
- Months aren't all the same length, so years+months+days arithmetic is approximate. This tool counts whole months from one birthday-anniversary to the next, then adds remaining days. Different conventions give different answers — Wikipedia's "age at date" is the same as ours.
- Why does total days lived sometimes differ from years×365?
- Leap years. Years average 365.25 days, so a 30-year-old has lived ~10,957 days, not 10,950. The tool counts exactly using actual calendar days.
- What about time zones?
- The calculator uses the date you entered as-is, without applying time zone shifts. Your "actual" age in seconds depends on what time of day you were born, which isn't captured in a date field.
Last updated: May 17, 2026