Validate date strings for correct format, leap years, and logical validity.
The Date Validator checks whether a date is a real calendar date, handling leap years and month lengths correctly, and tells you which format it recognized. It understands ISO (2026-09-30), US (09/30/2026), day-first (30/09/2026) and written dates such as "September 30, 2026", and warns when a date like 03/04/2026 could be read two ways.
Made for developers. Typical uses:
It checks one date at a time and cannot know your intended locale, so all-numeric dates with day and month both 12 or less are flagged as ambiguous rather than guessed.
Accuracy: Checks follow the published rules for each format. A passing result is a strong signal, not a guarantee that every system will accept the input.
Syntax and format checks find broken markup, bad JSON and mistyped numbers, but not meaning, business rules, email deliverability or whether a URL is alive.
Explore more in Validators, read the guides and articles, or see how we test our tools.
Test and debug regular expressions in real-time.
Best for testing regex patterns before using in code
Validate JSON data against JSON Schema specifications.
Best for confirming an API request body matches the schema documented in an OpenAPI spec before deploying
Calculate the exact number of days, months, and years between any two dates.
Best for counting the days until a holiday, exam or deadline
Calculate your exact age in years, months, days, hours, minutes, and seconds.
Best for checking an exact age for a form or application
Validate email addresses for correct format and syntax.
Best for validating email inputs in web forms