Identify the day matching a date

Identify the day matching a date. Handy for teams and individuals planning schedules, checking deadlines or preparing a document.

Identify the day matching a date. See a clear result update immediately in your browser, with no account, upload or stored data to worry about.

How to use

Enter a date in YYYY-MM-DD format in the input field.
Check that the day and month use two digits, such as 2025-12-25.
Run the search to get the weekday that matches the date.
Read the result on the right, then clear it if you want to test another date.

Example

With the provided example, the date falls at the end of the year. After running it, look at the displayed weekday and confirm that it matches the date you entered. This is useful for checking a deadline or preparing a schedule without manual counting.

Input

2025-12-25

Output

jeudi

Limits and formats

The expected format is YYYY-MM-DD; a date written differently may be rejected or misread.
The tool does not handle times, time zones or calendars other than the current one.
An impossible date, such as February 31, cannot produce a valid weekday.
The result should be checked for historical uses where the calendar changed.

Where processing happens

Everything runs in your browser: the weekday is calculated locally from the date you enter. Your input is never uploaded, shared or stored.

Frequently asked questions

Can I use a date like 12/25/2025?

The tool expects a date in YYYY-MM-DD format. A slash-based format may not be recognized. Convert your date to 2025-12-25 first to avoid ambiguity and get a reliable result.

Does the displayed weekday account for leap years?

Yes, the calculation follows the current Gregorian calendar and takes leap years into account. You can therefore test a February 29 date to check whether it exists in the chosen year and which weekday it falls on.

Can I find the weekday of a very old date?

Yes, as long as the date is valid in the calendar used by the tool. For historical dates before a calendar change, the result may differ from old sources and should be checked against a suitable reference.