Choose a birth date
Use the date picker’s calendar date format. It does not accept arbitrary free-form date formats.
Age Calculator
Calculate age between two calendar dates.
Last reviewed: · Testing methodology
How to use
Get complete years and months, remaining weeks and days, and elapsed totals.
Choose the target date
The target must not be earlier than the birth date.
Calculate and check the convention
Read calendar years and months separately from total elapsed time. A legal or institutional rule may use a different anniversary convention.
Limits and questions
Inputs are processed in your browser. Analytics and advertising can make separate network requests.
A result you can check
January 31, 2025 to February 28, 2025 is one calendar month under this convention.
Before using the result
Use the rule specified by the receiving form, institution or jurisdiction for eligibility decisions.
Frequently asked questions
- How does February 29 work?
- A missing anniversary date clamps to the last day of the target month. This is an arithmetic convention, not a ruling about a legal birthday.
- Are seconds the exact time since birth?
- No. The input contains dates only. Seconds are derived from elapsed whole dates assuming 24-hour days.