Find what day of the week any date falls on using Zeller. Day of the Week Finder is a free online tool from the ToolsRift Everyday Tools collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
It uses Zeller's congruence, a classic formula that computes the weekday directly from the day, month and year of a proleptic Gregorian date — no calendar lookup needed.
Yes, for dates in the Gregorian calendar. Note that many countries adopted the Gregorian calendar at different times before the 1900s.
Enter your date of birth and the tool tells you instantly which day of the week you were born.