Doomsday Trainer
Doomsday Trainer is made and published by Maarten Claessen. AppBrain is an independent app data site and isn't affiliated with Maarten Claessen. The app name, icon, screenshots and description belong to Maarten Claessen and are shown as published on the App Store.
AppBrain's verdict
- Rating on App Store
- 4.00
- 2 ratings
- Last updated
- September 15, 2026
- Size
- 15.2 MB
It doesn't have enough ratings yet to judge what users think.
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Store listing
By Maarten Claessen, from the App Store
Description by Maarten Claessen Written by the developer, not by AppBrain. Click to read.
PLAY
Build your streak and beat the clock. Every correct answer adds to your streak; one wrong answer ends it. Compete on the global leaderboard for Longest Streak and Fastest Average Speed.
BATTLE
Challenge a real opponent to a live 1-on-1 race. Five dates, fastest and most accurate player wins. Elo-based ranking tracks your competitive record.
TRAIN
Six methods to choose from:
• Doomsday — the classic anchor-day approach
• Odd + 11 — the Fong-Walters mental shortcut
• The Wollin Shortcut — a memory-based system using vectorized doomsdays, the Square Knot Rule, and the Wollin Calamity Table (by u/Nillows)
• Conway's Method — the original algorithm by John Conway
• Mod 28 — reduce any year to under 28 before calculating
• Custom Mode — pick your own date range, century, or decade
DRILL
Targeted practice for each component: months, centuries, years, mod 7 arithmetic, and the full Wollin Shortcut drill suite.
TUTORIAL
New to the algorithm? The built-in tutorial walks you through everything step by step.
Safety and technology
Found in the app by AppBrain- Price
- Free
- App size
- 15.2 MB
- Content rating
- Everyone
Technologies used by Doomsday Trainer
Releases
Updates seen on the App Store- Version
- 1.3.9
- Launched
- March 2026
No changelog data
Alternatives
Similar apps and more from Maarten Claessen
Rankings
App Store top chartsApp Store Rankings for Doomsday Trainer
About the app and developer
About Doomsday Trainer
Doomsday Trainer is an education app developed by Maarten Claessen.
What is the rating of Doomsday Trainer?
Doomsday Trainer is rated 4.00 out of 5 stars, based on 2 ratings.
Is Doomsday Trainer free?
Doomsday Trainer is free. The app size is 15.16 MB. The latest version available is 1.3.9. The last update was on September 15, 2026.
What are the requirements for Doomsday Trainer?
The app has a content rating of Everyone. The app has been available on the App Store since March 2026.
Developer information for Maarten Claessen
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