Age Difference Calculator
Enter two dates of birth to find the exact age gap between two people, in years, months, and days. The order you enter them in doesn't matter.
How to calculate age difference
Take the two dates of birth and count the whole years, months, and days between them, exactly as you would for a single age. Whoever was born earlier is the older person; the gap is the same whichever order you enter the dates.
Gap = calendar difference between the two birth dates (years, months, days)
Worked example
One person born 1 January 1990, the other born 1 January 1995.
- Whole years between the dates: 5
- Leftover months: 0
- Leftover days: 0
Result: 5 years, 0 months, 0 days apart (1,826 days, including two leap days)
Frequently asked questions
How do I calculate the age difference between two people?
Enter both dates of birth and the calculator counts the exact calendar gap in years, months, and days. By hand, count the whole years from the earlier date, then the leftover months and days.
Does it matter which birthday I enter first?
No. The calculator always reports the gap as a positive value, so you can enter the two dates in either order and get the same answer.
Why is a 5-year gap sometimes 1,826 days, not 1,825?
Because leap years add a 29th of February. A five-year span usually contains one or two leap days, so the exact day count is a little more than 5 × 365.
Can I compare any two dates, not just birthdays?
Yes. The tool works for any pair of dates, so you can also measure the time between two events, anniversaries, or milestones.