Doomsday Trainer
Doomsday Trainer is made and published by Inefficient Code. AppBrain is an independent app data site and isn't affiliated with Inefficient Code. The app name, icon, screenshots and description belong to Inefficient Code and are shown as published on Google Play.
AppBrain's verdict
Niche- Total installs
- 1 thousand
- Last updated
- September 13, 2026
Doomsday Trainer is a niche app, with 1 thousand installs. It doesn't have enough ratings yet to judge what users think.
Installs
Tracked by AppBrain- Last 30 days
- 170
- Play install range
- 1+ thousand
- Launched
- March 2026
Installs over time
Doomsday Trainer has been installed 1 thousand times. Over the past 30 days, it has been installed 170 times.
Rankings
Google Play top chartsGoogle Play Rankings for Doomsday Trainer
Competitors
Similar apps and more from Inefficient CodeReleases
Updates seen on Google Play- Version
- 6.1.5
- Launched
- March 2026
User feedback
Ratings and reviews on Google PlayComments on Doomsday Trainer for Android
Technology
Found in the app by AppBrain- Ads
- No ads
- Price
- Free
- Libraries
- ?
- App size
- 13.3 MB
- Content rating
- Everyone
Technologies used by Doomsday Trainer
About the app and developer
About Doomsday Trainer
Doomsday Trainer is an educational app developed by Inefficient Code.
Install Statistics
Doomsday Trainer has been installed 1 thousand times. In the last 30 days, the app was installed 170 times.
User Ratings
The app has no ratings yet.
App Information
Doomsday Trainer is freely available from Google Play. The app size is 13.33 MB. The latest version available is 6.1.5. The last update was on September 13, 2026.
Technical Requirements
The app has a content rating of Everyone. The app has been available on Google Play since March 2026.
App Performance Report
Get a detailed PDF report for Doomsday Trainer with download trends, rating history, and key performance statistics — useful for competitive research or tracking your own app. Learn more
Get PDF Report — $29Developer information for Inefficient Code
Frequently asked questions about Doomsday Trainer
Is Doomsday Trainer free?
Yes. Doomsday Trainer is free on Google Play.
Is Doomsday Trainer still available?
Yes. Doomsday Trainer is on Google Play, and the last update we saw was on September 13, 2026.
Does Doomsday Trainer contain ads?
No. Google Play does not list Doomsday Trainer as containing ads.
How large is Doomsday Trainer?
Doomsday Trainer is 13.33 MB.
Is Doomsday Trainer suitable for children?
Google Play rates the content of Doomsday Trainer as suitable for everyone.
How many times has Doomsday Trainer been installed?
Google Play lists 1,000+ installs for Doomsday Trainer.
Who made Doomsday Trainer?
Doomsday Trainer was developed by Inefficient Code. It is listed in the educational category on Google Play.
What are the best alternatives to Doomsday Trainer?
People looking at Doomsday Trainer also look at these educational apps: Doomsday Clock, LuckRoll, Multiplication | Times Tables, Time Since, Tetraquism: Block Puzzle Game.
Store listing
By Inefficient Code, from Google Play“Calculate the day of the week for any date in history. Train your brain!”
Description by Inefficient Code Written by the developer, not by AppBrain. Click to read.
Doomsday Trainer — Name Any Day in Your Head teaches you the mental calendar calculation techniques used by competitive memory athletes and calendar savants. Start slow, build the skill, then race the clock.
🎮 THE GAME
Every round, you're shown a random date from across the centuries. Your goal: name the correct day of the week as fast as possible.
• Build Your Streak: Answer correctly and your streak grows. Answer wrong and it's over.
• Beat the Clock: A countdown timer keeps the pressure on, getting tighter the longer your streak runs.
Build the longest streak. Set the fastest average speed. Climb the global rankings.
🧠 FIVE METHODS TO MASTER
Not everyone thinks the same way. Doomsday Trainer teaches five proven calculation techniques, each with its own step-by-step training mode:
• Doomsday: The classic anchor-date method used by world memory champions.
• Wollin Shortcut: A two-part system using vectorized Doomsday codes and Doomyear sequences for lightning-fast results.
• Odd + 11: An elegant carry-free approach with no multiplication.
• Mod 28: Subtract chunks of 28, count leaps, done.
• Conway: Dozens, remainder, and leaps in one smooth pass.
Training mode walks you through every calculation step-by-step, featuring progressive hints, a full reference Databank, and a built-in Wollin lookup table.
🎯 FOCUSED DRILLS
Isolate the parts that slow you down. Eight targeted drill modes sharpen the individual skills that feed into every calculation:
• Month Anchors
• Century Anchors
• Year Offset
• Modulo 7
• Add / Subtract
• Times Tables
• The Wollin Shortcut
• Leap Year Detection
Track your progress across every drill category with detailed accuracy breakdowns and improvement charts.
⚔️ BATTLE REAL OPPONENTS
Challenge players around the world in real-time 1v1 Best-of-5 matches.
• Fair Competition: Both players receive identical dates (same seed, same sequence), so the result is pure speed and accuracy.
• Ghost Matchmaking: No live opponent online? The game instantly matches you with a ghost recording of a real player from your skill range.
• Rank Up: Earn Elo rating and climb the competitive 1v1 leaderboard.
🌍 GLOBAL LEADERBOARDS
Compete for the top of two global rankings. Your scores sync automatically so you can see exactly where you stand worldwide.
• Longest Streak: How many correct answers in a row can you get?
• Fastest Speed: What's your best average over 5 consecutive answers?
📈 TRACK YOUR PROGRESS
• Speed and accuracy charts for the past 7 days, 30 days, or full year.
• Personal best streak and speed records.
• Training and drill completion history.
• Full game-by-game breakdown.
✨ FEATURES
• Multiple visual themes to customize your experience.
• Adjustable font size and layout options.
• Full coverage of edge cases, including leap year handling and century shifts.
Whether you're a memory sports competitor, a maths enthusiast, or just someone who wants a genuinely unusual party trick — Doomsday Trainer will get you there.
Recent changes:
New in v6.1.5: Integrated explanation engine