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Age Calculator

Counts completed calendar years, then separately calculates elapsed calendar days.

Your inputs stay in your browser. No account required.
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How Age Calculator works

Counts completed calendar years, then separately calculates elapsed calendar days.

Try an example

21 August 2000 to 9 September 2026 → 26 years.

Good to know

Date-only calculations use the Gregorian calendar and UTC day boundaries, so daylight-saving changes do not alter day counts. Years 0001–9999. A 29 February birthday advances on 1 March in non-leap years.

Your privacy

Processing happens on this device for this tool. We do not upload your input, put it in share links or save it to your favourites. Closing this tab discards the working input; downloaded results remain wherever you save them.

When this tool is useful

Use the age calculator for a completed calendar age and an explicit elapsed-day count between a birth date and a reference date.

How to use it

  1. Enter the birth date and choose the reference date, defaulting to today on your device.
  2. Read the completed years and the separate calendar-day result.
  3. For official records, verify the date convention and time zone used by the responsible organisation.

Checks before you rely on the result

  • The calendar result is not a medical or legal determination.
  • Dates are interpreted as calendar dates rather than hidden clock times.
  • Leap days and month lengths are handled explicitly; a browser clock can still be set incorrectly.

This page is maintained with the tool implementation and its deterministic tests. If the result looks wrong, report the issue with a non-sensitive example.

Read the Age Calculator instructions

A useful next step

Date Difference
Add / Subtract Days
Business Days Calculator
Made for clarity. Built to be useful.Report an issue