Your exact age is the time elapsed since your birth date, expressed in years, months, and days. Because months have different lengths, counting it precisely takes a little care — which is what this calculator does.
How age is counted
We count complete years first, then the leftover complete months, then the remaining days, borrowing from the previous month when needed. The result also shows your age as a total number of months and days, which is handy for milestones.
A worked example
Someone born on 15 January 1990, as of 20 March 2020, is 30 years, 2 months, and 5 days old. The calculator counts the 30 full years to 15 January 2020, then the two months to 15 March, then the five remaining days. It also reports the total — about 362 months, or roughly 11,022 days — which answers the “how many days have I been alive?” question in one step.
Why the day count needs the real calendar
Months range from 28 to 31 days, and leap years add a February 29th, so you can't just multiply years by 365. The calculator walks the actual calendar to handle both, which is why a birthday that hasn't yet arrived this year counts you as one year younger than your birth-year math might suggest.
Leap-day birthdays are the classic edge case: someone born on 29 February only gets an exact calendar birthday every four years, though they still age a full year like everyone else.