Doomsday Practice

Doomsday Practice helps you master the Doomsday algorithm: a mental math technique for calculating the day of the week for any date in your head.

LEARN Step-by-step lessons break the algorithm into digestible pieces. Understand the anchor days, memorize the Doomsday dates, and build a reliable mental framework at your own pace.

PRACTICE Drill random dates across any year or century. Get instant feedback, track your accuracy, and build speed through repetition.

REVIEW A clean reference sheet keeps the key rules and mnemonics at your fingertips while you're still building fluency.

TRACK YOUR PROGRESS Streaks and stats keep you accountable. Watch your accuracy and response time improve over time.

Whether you're a mental math enthusiast, a memory competitor, or just want a party trick that actually impresses people: Doomsday Practice gets you there.