How to use it
- Type the first date of birth as YYYY-MM-DD.
- Type the second date of birth.
- Read who is older and the gap in years, months and days.
How it works
The calculator takes the earlier date and adds whole months until adding another would pass the later date. Those months give the years and months of the gap; the days between that point and the later date are the days. A month-end birth date is clamped to the last day of a shorter month, so 31 January plus one month is 28 February (29 in a leap year). Total days are the plain difference between the two dates, and total weeks are those days divided by 7, rounded down.
Worked example
Person A was born on 15 May 1990, person B on 20 August 1993. Counting from 15 May 1990, 3 years and 3 months reach 15 August 1993, and 5 days more reach 20 August. The gap is 3 years, 3 months and 5 days. In days: 1,096 days to 15 May 1993 (1992 was a leap year) plus 92 to 15 August plus 5, which is 1,193 days, or 170 whole weeks.
Good to know
- Only calendar dates are used, so time zones do not change the answer.
- Two people born on the same day have a gap of zero.
- For the exact age of one person on a given day, use the age calculator.