What is the Day of the Week tool?

Find the weekday for any date (Zeller algorithm). This free online tool is available at NumbersChecker with no login required.

Is the Day of the Week tool free?

Yes, the Day of the Week tool is completely free to use at NumbersChecker. No account or installation is needed — results are instant.

How do I use the Day of the Week tool?

Enter your input into the form at https://numberschecker.com/tool/day-of-week, click Run, and the result appears instantly. Click any result value to copy it to your clipboard.

Is there an API for the Day of the Week tool?

Yes. Send a POST request to https://numberschecker.com/api/day-of-week with your input as a JSON body. The API is free and requires no authentication.

Date & Time weekdaycalendardate

Day of the Week

Find the weekday for any date (Zeller algorithm).

About the Day of the Week Tool

Find the weekday for any date (Zeller algorithm). This free online tool runs entirely in your browser — no login, no installation, and no data is stored.

This tool is part of the Date & Time category on NumbersChecker. Browse all Date & Time tools or explore all 139 tools.

Related: weekday · calendar · date

API usage

POST /api/day-of-week
Content-Type: application/json

{
  "text": "your input here"
}