The Discordian or Erisian calendar is an alternative calendar used by some adherents of Discordianism. It is specified on page 00034 of the Principia Discordia.

The Discordian year 1 YOLD is 1166 BC. (Elsewhere in the Principia Discordia, it is mentioned that the Curse of Greyface occurred in 1166 BC, so this is presumably the start-date of the calendar.) As a reference, 2012 AD is 3178 YOLD (Year of Our Lady of Discord). While the abbreviation "YOLD" isn't used in the Principia, and the phrase "Year of Our Lady of Discord" is only mentioned once, it is a Discordian tradition to use that designation.

The Discordian calendar has five 73-day seasons: Chaos, Discord, Confusion, Bureaucracy, and The Aftermath. The Discordian year is aligned with the Gregorian calendar and begins on January 1, thus Chaos 1, 3178 YOLD is January 1, 2012 Gregorian.

The Erisian week consists of five days: Sweetmorn, Boomtime, Pungenday, Prickle-Prickle, and Setting Orange. The days of the week are named after the five basic Discordian elements: Sweet, Boom, Pungent, Prickle, and Orange. There are 73 of these weeks per year and every year begins with Sweetmorn.