Age on a date
Calculate age in completed years on your chosen date.
How do I use this calculator?
Enter values using the stated units. The result updates as you type. To compare two situations, keep the same units and change only the relevant inputs.
The formula
Completed years = difference in years, minus 1 if the birthday has not yet occurred.
For a birth on 29 February, the additional year is counted on 1 March in a non-leap year.
A practical example
Here is the calculation with the values shown on opening. You can restore them with the reset button.
| Date of birth | 1990-05-15 |
|---|---|
| As of | 2026-09-07 |
| Age | 36 years |
The result corresponds to these inputs and the stated formula. Displayed decimals are rounded to at most six places; calculations retain the available precision until display.
Frequently asked questions
How can I check the result?
Use the formula “Completed years = difference in years, minus 1 if the birthday has not yet occurred.” with your own values. First check the units and stated conditions, then compare your result with the tool.
Are my data saved?
The entered values are used only for the calculation in your browser. The application does not send them to a calculation service or retain them after reload. See the privacy policy for hosting operations.
Why does the calculator show an error?
An empty field, division by zero or a value incompatible with the formula may prevent calculation. The message explains the correction needed. You may use a dot or comma for decimals.
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Texte : Age on a date · https://eseogen.com/calculatrices/age/?mp_lang=en