Age Calculator
Calculate age accurately between a birth date and a reference date.
Enter your values
Use the fields below, then select Calculate. Your result appears immediately on this page.
How to use the Age Calculator
Select a date of birth and a reference date. The calculator compares calendar dates so birthdays and leap-year boundaries are handled correctly.
Formula / calculation logic
Completed years are counted first, then the remaining completed months and days between the two calendar dates.
Worked example
A person born on 15 January 2000 is 26 years old on 21 August 2026.
Important notes
The reference date cannot be earlier than the birth date. Results use local calendar dates rather than an approximate days÷365 calculation.
Frequently asked questions
Does it handle leap years?
Yes. Calendar arithmetic is used instead of assuming every year has 365 days.
Can I calculate age on a past date?
Yes, as long as the reference date is on or after the birth date.