Age Difference Calculator

How far apart are two birthdays? Enter two dates of birth and get the exact gap in years, months and days.

First date of birth

Second date of birth

Select both dates of birth to see the exact age difference

The gap between two birth dates

Age gaps are usually quoted in whole years — "they're four years apart" — but the exact difference is more interesting: 4 years, 7 months and 12 days. Enter both dates of birth and the calculator gives you the precise breakdown, plus the total day count between the two birthdays.

The same math answers celebrity trivia ("how much older is X than Y?"), sibling gaps, relationship age differences and even pet-vs-owner comparisons. Anyone or anything with two birth dates works.

How the difference is computed

The calculation is the same calendar-exact years-months-days math this site uses for age — just applied between the two birth dates instead of birth-to-today. Calendar months and leap years are fully accounted for, so the result is not a rough 365-day approximation.

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Frequently asked questions

＋How do I calculate the age difference between two people?

Enter both dates of birth above. The calculator shows the exact difference in years, months and days, plus the total number of days between the two birthdays.

＋Which date should I enter first?

Order doesn't matter — the result is the absolute gap between the two dates, always shown as a positive difference.

＋Can I use it for anything besides people?

Yes. Any two dates work: pets, companies, buildings, historical events. If both have a known start date, this calculator gives you the exact time between them.