ClarityKitFind a tool
Date & time

Age Calculator

Find completed years of age and total elapsed calendar days between two dates.

Date conventions explained belowClear start and end values

Set your dates & time

Runs on your device

TIME SUMMARY

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter date of birth, age on date.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Subtract birth year from comparison year, then subtract one if the birthday has not yet occurred. For February 29 birthdays, this tool uses February 28 in non-leap years.

A WORKED EXAMPLE

Someone born on June 15, 1996 is 30 on June 15, 2026, and 29 on June 14, 2026.

What to keep in mind

This is calendar arithmetic, not a legal age determination. Leap-day birthday rules differ by jurisdiction. Dates are processed without time zones.

Common questions

What does completed years mean?

It counts full birthdays that have passed, rather than rounding partial years.

How are leap-day birthdays handled?

February 29 is treated as February 28 in a non-leap comparison year. Legal conventions may differ.

Methodology maintained by ClarityKit. How these tools are built and checked.