About
Select any date to instantly see what day of the week it falls on. Uses Zeller's formula, handles any date after 1582. All calculations run locally.
FAQ
Is this tool free?
Completely free. Part of Free ToolBase, no signup or payment required.
Is my data uploaded to a server?
No. All processing runs entirely in your browser. Your data never leaves your device.
Which browsers are supported?
All modern browsers: Chrome, Firefox, Safari, Edge. Latest versions recommended.
Can I use it on mobile?
Yes. Fully responsive design works on phones and tablets.