Day of the Week Calculator

Find the weekday for any calendar date.

Day of the Week Calculator helps you find the weekday for any calendar date. Enter date, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Day of the Week calculator does Day of the Week Calculator is built for dates, durations, ages, and schedules. Find the weekday for any calendar date. You enter date, then Simple Calculators computes the result instantly. Calendar math follows common civil-calendar rules used in everyday planning. How the math works Enter a Date. The calculator counts the days between it and Monday, January 1, 2001, divides by 7, and uses the remainder to step forward or back from Monday, since whole weeks don’t change the weekday. It also shows the day number in the week (Monday = 1), the week number of the year, the day of the year, whether it is a leap year, and the dates around it. The formula: Weekday = Monday + (days since Monday, Jan 1, 2001 ÷ 7, remainder). Every 7 days the weekday repeats, so only the remainder matters.