Age & DatesDATE & AGE TOOL
Age Difference Calculator
Compare two dates of birth and calculate their exact calendar difference.
How this calculator works
This tool uses calendar dates directly. Date differences are calculated from UTC-normalized calendar dates to avoid daylight-saving-time changes affecting the result. Calendar age counts complete months from the starting date, then remaining days. When a month is shorter, the date is clamped to its last day. For this tool, a 29 February birthday is observed on 28 February in a non-leap year. These are calculation conventions, not legal eligibility rules.
Why use this tool?
It is designed for quick, transparent calculations without requiring an account. Your date inputs are processed in your browser by the current version of the site.
Frequently asked questions
Does this calculator account for leap years?
Yes. Calendar calculations use the actual dates in the Gregorian calendar, including leap years.
Do you store my date of birth?
The calculator processes dates locally in your browser. We do not send the entered dates as analytics events. See our privacy information for site analytics details.
Keep exploring
What is the age difference between two people?
Enter both birth dates in either order. The tool measures the calendar interval from the earlier date to the later one and also reports the total number of days apart.
Worked example
Birth dates of 1 January 2000 and 1 January 2001 are 1 calendar year and 366 days apart.