Find your exact age in years, months and days from any date of birth, plus total days lived, the weekday you were born and your next birthday countdown. Runs entirely in your browser — your numbers never leave this device.
The years/months/days breakdown borrows from the month before the reference date when the day count goes negative — the standard calendar convention. Birthdays on 29 February are observed on 28 February in non-leap years for the next-birthday figure.
Enter a date of birth and the date you want the age at — today by default. The calculator subtracts the two dates field by field (years, then months, then days) and applies the standard borrowing rule whenever a field goes negative: negative days borrow the length of the month preceding the reference date, and negative months borrow a full year. That is exactly how a person counts their own age, so 36 years, 4 months and 17 days means 36 birthdays have passed, then 4 whole months, then 17 days into the next month.
Alongside the breakdown, the tool reports your age in total days — every day counted individually on the calendar, leap days included — and as weeks plus remaining days. It also names the weekday you were born and works out your next birthday: the date, how many days away it is, and the age you will turn. For 29 February birthdays, the next birthday is observed on 28 February in non-leap years, the most common convention; in a leap year it falls on the 29th itself.
All arithmetic is done on whole calendar days, never on timestamps, so timezones and daylight saving cannot move an answer by a day. And like every Kwikfig tool, the calculation runs in your browser — a date of birth is personal data, and it is never uploaded or stored.
By calendar subtraction with borrowing — the same method you would use on paper. Subtract the birth date from the reference date field by field; when days go negative, add the number of days in the month before the reference date and reduce the months by one; when months go negative, add 12 and reduce the years by one. The worked examples above show the borrow happening.
Because they borrow differently. Some tools borrow a flat 30 days for every month, which is an approximation. This calculator borrows the actual length of the specific month before the reference date — 31 days when that month is October, 28 or 29 when it is February — which is the calendar-exact method.
Enter your date of birth and the tool names it. For example, 15 June 1990 was a Friday. The weekday is counted from a fixed anchor date on whole calendar days, so it is the same answer wherever in the world you ask.
The age breakdown itself needs no special case — the borrowing rule handles February lengths automatically. For the next-birthday figure, a 29 February birthday is observed on 28 February in non-leap years, the convention most registries and families use; in leap years it is the 29th.
Yes — the maths only needs a start date. Enter the founding, adoption or completion date as the 'date of birth' and any reference date, and the same years/months/days breakdown, total days and anniversary countdown apply.
No. This calculator runs 100% in your browser — your date of birth is processed on your own device and is never uploaded, stored or tracked. Close the tab and it is gone.
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