Age Calculator: Formula & Worked Example

Calculate age in years from date of birth. Calculate instantly in your browser with editable inputs, a worked example and clear assumptions. No account required.

How it is calculated

As-of year − Birth year, minus one if the birthday has not occurred

Counts completed calendar-year anniversaries. The as-of date must not precede the date of birth.

Worked example

Date of birth

2001-11-18

As of date

2026-09-08

Example result: 24 years

The interactive tool lets you edit every input and reset to this example. Calculations run in your browser.

Questions and answers

Are my calculator inputs sent to a server?

These calculations run in your browser. The calculator does not send your entered values to a calculation server or save them to your learning account.

Why can the result differ from a full spreadsheet model?

Each calculator uses the equation and assumptions shown on this page. Displayed values may be rounded. A workbook with different timing, fees, filters or source data can produce a different result.

Can I use the calculator without an account?

Yes. All 73 calculators are available to guest learners. The worked example shows the default inputs, and Reset restores them.

Related calculators

• Days Between Dates — Count calendar days from a start date to an end date.
• Business Days — Count weekdays between two dates, excluding Saturdays and Sundays.
• Weeks Between Dates — Calculate elapsed weeks between two dates.

All 73 calculators · Practise in the Excel Simulator

Interactive practice runs in your browser.