OneTool

Age Calculator

Exact age in years, months, and days — as of today or any date you choose.

Defaults to today.

Enter a birth date.

What is this tool?

This tool calculates a calendar-accurate age breakdown (years, months, days, and total days) between a birth date and either today or a custom 'as of' date — the same way people naturally count birthdays.

How to use it

  1. Enter a birth date.
  2. Optionally check “Custom date” to calculate age as of a specific date instead of today.
  3. Read the years/months/days breakdown and total day count.