🎂 Age Calculator
Exact age in years, months and days, plus total days lived and a countdown to the next birthday.
36 years 8 months 1 days
Calculated on your device, your birthdate is never transmitted.
How the age calculator works
The calculation walks the calendar rather than dividing day counts: full years from birthday to birthday, then full months, then leftover days, the same way age is legally reckoned. That handles unequal month lengths and leap years correctly: someone born 29 February completes a year of age on 1 March in non-leap years in most jurisdictions. Concretely, if the target date's month-and-day is still before your birthday this year, the tool counts one fewer full year and borrows the remaining months and days from the preceding calendar months, the same borrowing you'd do by hand, which is why the day figure never comes out negative.
Dividing days-lived by 365.25 gives a decimal "age" that drifts a day or two around birthdays, fine for estimates, wrong for forms and eligibility rules, which use the calendar walk this tool performs.
Frequently asked questions
How is exact age calculated?
Calendar-style: count complete years first (has this year's birthday passed?), then complete months, then remaining days. This matches how ages are used legally and administratively.
What about leap-year birthdays (29 February)?
In common years the birthday is generally observed on 1 March for legal purposes (e.g. UK law), though some jurisdictions use 28 February. This calculator counts the year as complete once the calendar reaches 1 March.
Why does "total days" not equal years × 365?
Leap years: roughly one year in four has 366 days. Thirty years of life spans about 10,957 days, not 10,950.
Can I calculate age at a date other than today?
Yes, set the "age at" date to anything: a form deadline, a school cutoff, a historical date.
Why can't I just divide the days by 365?
Because a calendar year is 365 or 366 days, so dividing by 365 slowly overstates age, by roughly a day every four years, and the result drifts across each birthday. For casual estimates it's close, but forms, eligibility rules and legal age all use the calendar-walk method this tool performs, which lands on the exact birthday every time.
How do I work out age in months or weeks?
Total complete months is years × 12 plus the leftover months from the breakdown; weeks are the total days lived divided by seven. Age in months is common for babies and toddlers, while total days and weeks are handy for milestones, all shown here alongside the years-months-days figure.
Is my date of birth sent anywhere?
No, the calculation runs entirely in your browser. A birthdate is personal data; that is exactly why this tool is client-side.