Which Day Calculator

The Which Day Calculator is a simple tool that helps you determine the day of the week for any given date. Whether you’re planning an event or looking back at a specific day in history, this tool makes it easy to find out which day of the week it falls on.

What Does Which Day Calculator Do?

The “Which Day Calculator” allows users to input a specific date and then calculates the corresponding day of the week. This tool is especially useful for planning events, remembering anniversaries, or simply satisfying curiosity about a particular date.

Which Day Calculator Formula

To calculate which day a specific date falls on, you can use the following formula:

Day of the Week = (Day + Month Code + Year Code + Century Code) % 7

Where:

• Day is the day of the month (e.g., 15).
• Month Code is a predefined number based on the month (January = 1, February = 4, etc.).
• Year Code is a value assigned to the last two digits of the year (e.g., 2023 gives 23).
• Century Code is a number assigned to the century (e.g., 2000s = 6).

This formula will give you a number between 0 and 6, where each number corresponds to a day of the week (0 = Sunday, 1 = Monday, etc.).

Which Day Calculator Example

Example 1: Date in 2023

Let’s say you want to find out which day January 15, 2023, falls on. Using the formula, we calculate:

• Day = 15
• Month Code for January = 1
• Year Code for 2023 = 23
• Century Code for 2000s = 6

Day of the Week = (15 + 1 + 23 + 6) % 7 = 45 % 7 = 3

The result is 3, which corresponds to Wednesday. Therefore, January 15, 2023, was a Wednesday.

Example 2: Date in 1990

Now, let’s find out which day December 25, 1990, falls on. We calculate:

• Day = 25
• Month Code for December = 12
• Year Code for 1990 = 90
• Century Code for 1900s = 2

Day of the Week = (25 + 12 + 90 + 2) % 7 = 129 % 7 = 3

The result is 3, which corresponds to Tuesday. Therefore, December 25, 1990, was a Tuesday.

The “Which Day Calculator” is a convenient tool for determining the day of the week for any given date. Whether you’re planning future events or revisiting significant dates in history, this tool can quickly give you the day of the week, making it easy to organize and reflect on dates with accuracy.