Age Calculator
Calculate your exact age in years, months, and days from your date of birth — plus total days, weeks, and time until your next birthday.
How it works
How age is calculated
Age = target date − date of birth, in calendar units Days borrow from the previous month; months borrow from years
Age counts completed calendar years, then completed months, then leftover days. Because months have different lengths, the day count borrows from the actual previous month — which is why the same number of total days can produce different year/month/day breakdowns depending on the dates.
Worked example
Born June 15, 1995 and checking on July 19, 2026: that's 31 years, 1 month, 4 days — 11,357 total days. The next birthday is June 15, 2027.
Frequently asked questions
How does the calculator handle leap years?
Exactly — it uses real calendar dates, so February 29 birthdays and leap-year day counts are handled correctly. A February 29 birthday's 'next birthday' falls on March 1 in non-leap years.
Why do some age calculators give slightly different answers?
The years and total days always match, but the months/days breakdown depends on whether days are borrowed from the month before the target date or the month after the birthday. This calculator borrows from the month preceding the target date, the most common convention.
Can I calculate age at a past or future date?
Yes — set the 'Age at date' field to any date, for example to find how old someone was on a historical date or will be at graduation.