Date Time TOOL
Date Validator - Check If A Date String Is Real
Free online date validator. Checks any date string against the real calendar, catches February 29 in a non-leap year, explains exactly why a date is invalid, flags ambiguous 01/02/2026 input, and validates a whole pasted list. Runs in your browser.
Work with dates and times
Result
How to use this tool
- Enter or select your input.
- Run the tool and review the result.
- Copy or download the output when available.
About this tool
Free online date validator. Checks any date string against the real calendar, catches February 29 in a non-leap year, explains exactly why a date is invalid, flags ambiguous 01/02/2026 input, and validates a whole pasted list. Runs in your browser.
Frequently asked questions
Is my data uploaded?
This tool processes input in your browser. Files and text are not sent to our server by this page.