How to use Age Calculator
- Enter the date of birthPick the birth date in the Date of birth field. Any past date works.
- Set an optional reference dateLeave Age at date empty to use today, or choose another date to see the age on that day.
- Run the calculationPress Run Age Calculator to see the age in years, months and days, the total number of days, the next birthday and the days until it.
Common uses
- Checking eligibility for an age-limited form or program
- Finding someone’s exact age on a past or future date
- Counting the days someone has been alive
Frequently asked questions
How do I use Age Calculator?
1. Enter the date of birth: Pick the birth date in the Date of birth field. Any past date works. 2. Set an optional reference date: Leave Age at date empty to use today, or choose another date to see the age on that day. 3. Run the calculation: Press Run Age Calculator to see the age in years, months and days, the total number of days, the next birthday and the days until it.
How is the age calculated?
The tool counts whole calendar years first, then whole months, then the remaining days, using real month lengths. Total days is the exact number of days between the two dates, so leap days are included. In years without 29 February, a 29 February birthday is counted on 28 February.
Which date counts as today?
If Age at date is empty, today is your device’s local date, which your browser sends with the form. Only if that is missing is the GigaTools server date in UTC used.
Can the reference date be before the birth date?
No. If the date of birth is after the reference date, the tool asks you to correct it. To measure the time between any two dates, use the Date Difference Calculator or the Date Calculator.
Is my date of birth stored?
The dates are sent to the GigaTools server for the calculation and the result comes straight back. The response is marked private and not cached, and the tool does not save the dates.