Age calculator

What is this tool?

Find the calendar age between a date of birth and a comparison date. This works entirely in your browser.

How to use it

1. Read the input labels and limits below, then choose the operation that matches your task.
2. Enter the date of birth in year, month, day order. Dashes appear automatically.
3. Choose the date to calculate age on; today is filled in automatically.
4. Select Calculate age to see complete years, months, remaining days and total days.
5. Check the result against the worked example or original file before copying, downloading or using it elsewhere.

Worked example

From 2000-01-15 to 2026-10-10, the age is 26 years, 8 months and 25 days.

Questions & limits

Calculates complete calendar years and months, then remaining days. February 29 anniversaries fall on February 28 in non-leap years. Dates stay in your browser.

Which date format should I use?

Enter year, month and day. Eight digits are automatically formatted with dashes.

How are leap-day birthdays handled?

February 29 anniversaries use February 28 in non-leap years. Legal definitions may differ. The comparison date cannot be earlier than the birth date.

Checking your result

Read the labels before entering a value, especially when switching an operation or unit. Start with a simple example whose answer you already know if you are unsure which mode to use. After changing an input, check that you are reading the new result rather than a value copied earlier. Invalid or incomplete inputs need correcting before the calculation can finish. For a form or deadline with specific rules, follow the destination’s requirements and use this page as a convenient calculation aid.