Age Calculator
Result
Age Calculator Popular The Age Calculator works out exactly how old you are in years, months and days from your date of birth. You can also set an 'age at' date to find how old you were (or will be) on any other day, plus your age in total months, weeks a — free online calculator.
Formula
- Age calculator. This page explains the stated calculation method and provides a worked example.
- The main inputs are Date of birth, Calculate age on. Enter them in the units and format shown in the calculator.
- Use the units, labels and assumptions shown beside each input so the formula is applied consistently.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Age
- Date of birth: 1990-01-01
- Calculate age on: 2026-10-31
A person born on 2000-01-01 is 26 years old on 2026-01-01.
Sample result: Calculating…
Frequently asked questions
What does the Age calculate?
Calendar age should be computed with real calendar dates rather than assuming every year has the same number of days.
Which values should I enter?
Enter Date of birth, Calculate age on using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Age = End date − Birth date.
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.