Enter two dates of birth to calculate the exact age difference between two people in years, months and days. The calculator also shows who is older and the total number of days between the two birth dates.
Both dates of birth are processed in your browser and are not stored.
Your age difference is fixed. Current ages change as birthdays pass, but the calendar gap between two dates of birth stays the same.
The calculator compares calendar dates only. It does not measure differences in birth times.
Want the full step-by-step method? This page focuses on the tool. For manual calculation steps, worked examples, and common mistakes, read our complete guide: How to Calculate the Age Difference Between Two People.
How to Use the Age Difference Calculator
- Enter Person 1’s complete date of birth.
- Enter Person 2’s complete date of birth.
- Select Calculate Age Difference to see the exact gap.
You can enter the two people in either order. The calculator identifies the earlier birth date automatically and reports the age difference, so the entry order does not affect the result.
Method: Age difference = Later DOB minus Earlier DOB.
Frequently Asked Questions
How do I enter the dates?
Enter each person’s complete date of birth, day, month, and year, into the two date fields, then select Calculate Age Difference. Use the full date for an exact result; the birth year alone is not enough.
Does it matter which person’s date of birth I enter first?
No. The calculator compares both dates, identifies the earlier birth date automatically, and reports the age difference. The entry order does not change the result.
Related Calculators and Guides
- How to Calculate the Age Difference Between Two People, full guide
- Calculate a person’s current age from their date of birth
- Read our age calculation methodology and edge-case rules
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