Comparison

Calvin Chess Trainer vs KarpaChess

Price, ratings, monetisation and update history for both apps, side by side โ€” with what reviewers say about each.

Head to head
About

Calvin Chess Trainer

Features
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Calvin Chess Trainer drills the skills that puzzles take for granted: seeing the whole board, and reading and finding squares and moves without thinking. Daily warm-up Five quick timed drills, about five minutes: find the checks, spot the loose pieces, find the forks, name squares from Black's side, then a mate in one. Vision โ€ข Find Checks: every check in a real game position โ€ข Find Captures: every capture on the board โ€ข Hanging Pieces: every undefended piece โ€ข Forks & Skewers: the squares that hit two targets โ€ข Knight Sight: every square a knight reaches โ€ข Knight Flight: the fewest moves to the target โ€ข Pawn Attack: slip past a wall of pawns โ€ข Mate in 1: 400 positions, one move to mate Notation โ€ข Squares: find the square, fast, from White's side or Black's โ€ข Files & Ranks: name every file and rank โ€ข Read Moves: read a move, then play it โ€ข Piece Letters: K, Q, R, B and N at a glance โ€ข Piece Values: which side comes out ahead? Opening Explorer Play through the openings with book moves, Stockfish hints and an evaluation bar. Practice your way โ€ข Practice at your own pace, or race the clock in timed rounds โ€ข Every drill remembers its setup, and Continue picks up where you left off โ€ข Results show the answers you missed โ€ข Personal bests, saved on your device โ€ข Squares and pieces spoken aloud as you play โ€ข Works offline No ads, no in-app purchases and no account. From Internut Education.

About

KarpaChess

Features
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KarpaChess teaches chess on the board. Every lesson shows you an idea, lets you play it, then asks you to prove it on a position you have never seen. Train on rated puzzles, play Stockfish 19 and study the masters, in twelve languages. Everything runs on your device: no account, no ads, no tracking. SEE IT, PLAY IT, OWN IT Each of the 100 lessons follows three beats. See the idea on the board, with arrows and moves played out for you. Play it yourself: if you are stuck, the hint is a sentence the lesson's author wrote for that exact position. Then own it, by solving a puzzle on a new position. The patterns you own go into your Pattern Book, and Sharpen brings them back before you forget them. EIGHT ARTS Foundations, The Story of Chess, The Blade (tactics), The First Moves (openings), The Finish (endgames), The Plan (strategy), The Hunt (attack) and The Chess World. They run from setting up the board to the Greek gift and the Lucena bridge. A RATED PUZZLE TRAINER 240 puzzles in twenty packs, rated from 600 to 2000, with solutions several moves deep. Your first try moves your puzzle rating. After that, replay any puzzle to beat your best. PLAY STOCKFISH 19 Four strengths, from beginner to full strength. Play with a real clock, increment included, or untimed. Ask for a hint, take a move back, and come back to an unfinished game where you left it. REVIEW EVERY MOVE When a game ends, every move is graded best, good, inaccuracy, mistake or blunder, and the turning point is explained. THE STUDIO A library of 240 short, decisive master games in 24 collections, from Paul Morphy in the 1850s to the present day. Import your own games as PGN, with their comments and variations kept. Brilliant moves are flagged, and the drawing tools put arrows, lines, highlights, shapes, a pen and text on the board. A HINT WHEN YOU ASK One hint button, answered on your device. It looks at material, king safety, pawn structure, development and loose pieces, and says what matters. MAKE IT YOURS Ten themes, five boards, ten original piece sets, three typefaces and three sound packs. TWELVE LANGUAGES English, French, Spanish, Arabic, Chinese, Russian, Indonesian, Japanese, Hindi, Turkish, Italian and Portuguese. The app, every lesson and every puzzle are translated by hand. PRIVATE BY DESIGN KarpaChess collects no data. It never connects to the internet, and everything it keeps stays on your device. FREE SOFTWARE KarpaChess is free software under the GNU GPL, version 3 or later. Its complete source code is published at https://github.com/mourad-ghafiri/KarpaChessMobile

Screenshots

Calvin Chess Trainer4 screens
KarpaChess4 screens

Verdict

The call

Calvin Chess Trainer and KarpaChess are too close to call on the numbers: across 6 compared parameters โ€” price, update cadence, ads and in-app purchases among them โ€” neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS

CostPrice ยท In-app purchases ยท Ads ยท Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Calvin Chess Trainer ships an update every 5 days, KarpaChess every 3 days. The most recent releases landed on October 19, 2026 and October 23, 2026 respectively.

ScorecardNo meaningful differences
Calvin Chess Trainer versus KarpaChess: the parameters behind the verdict, then further details
ParameterCalvin Chess TrainerKarpaChess
PriceFreeFree
Update frequencyEvery 5 daysEvery 3 days โ€” better
AdsNoNo
In-app purchasesNoNo
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.015.0
Further details โ€” not scored
Size170 MB171 MB
Age rating4+4+
DeveloperDAVID MARKLEMourad GHAFIRI

In-app purchases

None

Calvin Chess Trainer

No in-app purchases

None

KarpaChess

No in-app purchases

Questions

Is Calvin Chess Trainer free?
Calvin Chess Trainer is free to download, with no in-app purchases.
Is KarpaChess free?
KarpaChess is free to download, with no in-app purchases.
Do Calvin Chess Trainer or KarpaChess have ads?
Neither Calvin Chess Trainer nor KarpaChess shows ads.
Which is updated more often, Calvin Chess Trainer or KarpaChess?
Calvin Chess Trainer ships an update every 5 days, and KarpaChess every 3 days. Most recently, Calvin Chess Trainer was updated on October 19, 2026 and KarpaChess on October 23, 2026.

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