AgeGapCalc

AgeGapCalc is a free browser calculator for the age difference between two people. You enter two birth dates, add names if you like so the result reads naturally, and it returns the gap in years, months and days along with the total number of days. A swap button flips the dates and a copy button puts the answer on your clipboard. The page explains its method: it subtracts calendar parts and borrows a month or a year when a value goes negative, handling leap years and month lengths, including 29 February, instead of dividing a day count by 365. The calculation runs in the browser with no account, and the site says no data is collected. Related tools on the same site cover a single person's age, the duration between two dates and half-birthdays.