gizmobench

Age Gap Calculator

Enter two dates of birth and get the exact difference in years, months and days, plus the total in days and weeks. Worked out on real calendar months rather than an average, so the answer holds across leap years and short months.

Age gapReadyPick two dates of birth
First date of birth
Second date of birth

Common questions

Does the order of the dates matter?
No. The gap between two people is the same size whichever way round you enter them, and the calculator reports which date came first separately. That is different from the age calculator, where the direction genuinely matters.
Why not just subtract the years?
Because it is wrong by up to a year. Two people born in 1990 and 1994 might be three years and one day apart, or nearly five years. It depends entirely on the months and days. Subtracting birth years answers a different, vaguer question.
How are months counted?
On the real calendar. A month from 31 January is 28 February, not the 3rd of March, and February's length changes in a leap year. Working in average months of 30.44 days drifts by a day or more over a large gap, which shows up as an answer that disagrees with counting on a calendar.
What counts as a large age gap?
That is a social question rather than a mathematical one, and the answer varies by culture, context and the ages involved. A four-year gap means something very different at 16 than at 46. The calculator gives you the number; what it means is not something arithmetic can settle.
Can I use this for anything other than people?
Yes. It is just the precise distance between two dates. Equipment service intervals, warranty windows, the gap between two events. For a duration that includes times of day, the duration calculator handles hours and minutes as well.
Are the dates stored anywhere?
Only in your own browser, so the page remembers them next time. Nothing is uploaded.

Exact. Counted in calendar fields (years, then months, then days) from local midnight on each date, so a daylight-saving boundary cannot shift the answer by a day. Leap-day dates use the 1 March convention, stated on screen when one applies.