Age Calculator
Calculate your exact age from your birth date: full years, months and days up to today, how many days you've lived in total, and how many days are left until your next birthday. The calculation uses real calendar arithmetic, not an approximate division by 365 days.
How is it calculated?
Year, month and day of the reference date (today) are subtracted from those of your birth date, "borrowing" a month or a year whenever today's day or month hasn't yet reached your birthday's in the current month or year — the same method you'd use to work out an exact age by hand on a calendar, so it gives the correct result on leap years and with months of different lengths.
Examples
Born May 15, 1990, calculated on May 15, 2026 (birthday that same day)
36 years, 0 months and 0 days: today is their birthday, so the next one is 0 days away (the one a year from now).
Born February 29, 2000, calculated on February 29, 2028 (leap year, exact anniversary)
28 years, 0 months and 0 days. Since 2028 is a leap year, February 29 exists that year and the birthday falls exactly today.
Why dividing days by 365 isn't enough
A year doesn't always have 365 days (leap years have 366) and months don't all last the same — that's why this calculator subtracts year, month and day separately, like on a real calendar, instead of converting everything to days and dividing.
Dividing by 365 approximately can push your age in years forward or back depending on how many February 29ths you've lived through — a small error, but unnecessary when the exact calculation isn't any harder to code.
Next birthday and days lived
Besides the exact years, months and days, the calculator shows how many days are left until your next birthday (0 if it's today) and how many days you've lived in total since your birth date.
If what you need is the difference between any two dates (not your age up to today), the days between dates calculator solves that other intent with the same kind of precision.