Age Calculator
Age Calculator is a free time tool that runs directly in your browser with no account required.
About this tool
Enter a birth date and this calculator returns the person's age in completed years, along with the total number of days lived. An adjustable as-of date lets you compute age on any day, past or future, which is handy for eligibility cutoffs, school enrollment dates, or form deadlines rather than just today.
How to use
- Select the person's Birth date.
- Set the As of date to today or to the specific cutoff date you care about.
- Read the Age in completed years and the Total days lived between the two dates.
Frequently asked questions
How does the calculator handle birthdays that haven't happened yet this year?
It subtracts the birth year from the as-of year, then subtracts one more if the as-of date falls before the birthday's month and day. So someone born June 15, 1990 is 35 on June 14, 2026 and 36 on June 15, 2026.
Can I calculate age at a past or future date?
Yes. The As of date defaults to a fixed date but accepts any date, so you can answer questions like how old someone was on a contract signing date or will be at a program's start date.
What does Total days measure?
It is the whole number of days between the birth date and the as-of date, useful for milestones like a 10,000th day or precise duration requirements.
How are February 29 birthdays handled?
In non-leap years the birthday comparison uses month and day, so a February 29 birth date ticks over on March 1, once the calendar has passed February 29's month-and-day position.
Is any of this information stored?
No. The calculation runs entirely in your browser and the dates you enter are not sent to or stored on any server.