An exact age in years, months and days — as of today or any date.
Age in whole years is just how many birthdays have passed. The months-and-days remainder is counted by calendar: the calculator subtracts the birth month and day from the target date and, when the day comes out negative, borrows the length of the preceding calendar month — which is why the same gap can read as a slightly different number of days depending on the months involved. By default it measures age as of today, but you can set any target date to find an age on a past or future day — handy for working out how old someone will be at an event, or their age on a specific historical date. The totals in months, weeks and days are exact counts from the birth date. To count a plain gap between two arbitrary dates, use the date calculator.