Age Calculator
Exact age down to the day — plus a few numbers that make birthdays more interesting.
Defaults to today
Age
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Total days
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Total weeks
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Total months
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Next birthday
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Day of week born
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How exact age is calculated
Age in "years, months, days" counts complete calendar years first, then complete months, then leftover days — the way official documents and immigration forms expect it. Because months differ in length, two people born 31 days apart can have different "months and days" readings; the total-days figure is the unambiguous one.
Where precise age actually matters
- School cutoffs: kindergarten and sports leagues use strict "age on date X" rules.
- Applications: visa, exam and competition eligibility often specify age on a deadline date — set the "as of" field to that date.
- Pediatric doses & milestones: tracked in weeks and months, not years.
- Retirement & pensions: benefits switch on at exact ages (60, 65, 67…), sometimes to the month.
Leap-day birthdays
Born February 29? Legally, most jurisdictions treat March 1 (some, February 28) as your birthday in non-leap years. This calculator counts your next birthday as the next occurrence of Feb 29 — or Mar 1 when the year has no leap day.
Frequently asked questions
Why does my age in months not equal years × 12?
It does, plus the extra complete months since your last birthday. "Total months" counts every complete month since birth: a person exactly 20½ years old shows 246 total months.
Can I calculate age at a past or future date?
Yes — change the "age as of" field. Useful for "how old was I when…" and for eligibility deadlines.
Does it handle time zones?
Dates are interpreted in your device's local time zone. Around midnight or across hemispheres, a birth certificate's local date is the authoritative one.