Day of the Week Calculator

This calculator determines the day of the week for a given date. It uses the Zeller's Congruence algorithm, a well-known formula to calculate the day of the week.

Input Parameters

Zeller's Congruence algorithm works best with dates from 1582 onwards (Gregorian calendar)

Calculation Results

Calculation Formula (Zeller's Congruence)

h = q + floor((13(m+1))/5) + K + floor(K/4) + floor(J/4) + 5J

Where:
h = Day of the week (0 = Saturday, 1 = Sunday, 2 = Monday, ..., 6 = Friday)
q = Day of the month
m = Month (3 = March, 4 = April, ..., 14 = February)
K = Year of the century (year % 100)
J = Zero-based century (year / 100)

Day of the Week Calculator Calculator Usage Guide

Learn how to use the Day of the Week Calculator and understand its working principles

How to Use

  1. Enter the year (1582 or later), month, and day in the input fields.
  2. Click the "Calculate" button to determine the day of the week.
  3. The result will show both the input date and the corresponding day of the week.

How It Works

This calculator uses Zeller's Congruence, an algorithm devised by Christian Zeller to calculate the day of the week for any Julian or Gregorian calendar date. The formula takes into account the peculiarities of the calendar system and provides accurate results.

Limitations

The algorithm works best with dates from 1582 onwards, when the Gregorian calendar was introduced. For dates before this period, you might need to use a different calculation method or adjust the formula accordingly.

Example

If you enter June 15, 2023, the calculator will determine that it's a Tuesday.