Day of Week Calculator
Find out what day of the week any date falls on — past or future
Enter a Date
// Doomsday Algorithm
John Conway's Doomsday algorithm lets you mentally calculate the day of week for any date. Key anchor days: 4/4, 6/6, 8/8, 10/10, 12/12 all fall on the same weekday each year.
// ISO Week Number
ISO week 1 is the week containing the first Thursday of January. Some years have 53 weeks. Week numbers are used in European business contexts.
// Friday 13th
Every year has at least one Friday the 13th. The most in one year is three (when Jan 1 falls on Thursday in a non-leap year).
// Born on a Monday
"Monday's child is fair of face…" — the old nursery rhyme assigns personality traits to birth weekdays. About 1 in 7 people share any given birth weekday.