Date
Age Calculator
Age calculation rules
The age calculator compares a birth date with a reference date and returns the completed age in full years.
It also shows elapsed days and the remaining distance to the next birthday, so the result is useful for forms, anniversaries, and planning.
How to read the result
The main value is exact age on the reference date. Supporting values explain where that date sits in the current age year.
If the reference date is before the birth date, the page keeps the input visible and explains that the range is not valid.
Examples
Age on a specific date
Set the reference date to a form deadline, school year date, or contract date.
Birthday countdown
Use today as the reference date to see how many days remain until the next birthday.
Limits
- The result is a date calculation, not legal or administrative advice.
- Timezone and birth time are not used.
- Input state can be shared through the URL, so avoid sensitive personal details.