Anchor days

Anchor days

The first number you need in order to work out the doomsday for a year is its anchor day. Anchor days are specific to the century the date falls in.

Each century is linked to a specific anchor day, and since our calendar repeats every 400 years, there are only four anchor days you need to memorise.

These weekday numbers simply have to be memorised. Luckily, in most everyday situations, the dates you want to convert to weekdays fall in one or two of these centuries. Knowing that years in 19xx have Wednesday as their anchor and years in 20xx have Tuesday is enough for almost every practical use.