How to use
Enter the date of birth and the date on which age should be measured, then calculate. The reference date may be today, a past date, or a future date, but not before birth.
How age is calculated
Completed calendar years are counted first, then completed months, then remaining days. Total days is the exact whole-day difference between the two dates.
For a February 29 birth date, this page treats February 28 as the birthday in non-leap years. The convention is shown because legal and cultural rules can differ.
Examples and limits
A person born 2000-02-29 is 22 years old on 2023-02-27, with the next birthday on 2023-02-28 under this page’s convention.
This is general calendar arithmetic, not a decision about legal majority, school eligibility, insurance, medicine, benefits, or local law. Years are limited to 0001–9999.
Frequently asked questions
What does chronological age mean?
It is the number of complete calendar years, then months and days, elapsed since birth.
How are leap-day birthdays handled?
February 28 is used in non-leap years on this page, and February 29 in leap years.
Can this determine legal age?
No. Legal rules vary by place and purpose.