Best Logic Puzzle Apps: Pure Deduction, No Luck

For pure deduction on iPhone, start with a sudoku app: Good Sudoku if you want the deepest technique list and will pay once to unlock it, Sudoku Royale if you want it free with no ads and lessons built in. Nonogram.com and Killer Sudoku by Sudoku.com are the best picks outside classic sudoku. Crossmath and Arcadia Zen Math are logic with arithmetic mixed in. Block puzzles, mahjong solitaire and trick riddle games are fun, but part of each depends on luck, hidden tiles or wordplay rather than reasoning.

The test we use on this page is simple: can every move be worked out from what is on the screen? If yes, it is a logic puzzle. If a random piece, a tile you cannot see or a trick in the wording can decide the outcome, it is a different kind of game, even when the App Store files it under logic.

The App Store facts

From each app's US App Store listing, checked October 26, 2026. Prices and paid items change, so check the listing before you buy.

Logic or luck: the test, app by app

Why sudoku is the cleanest logic puzzle

A well-made sudoku has exactly one solution, and every digit can be reached by a chain of deductions from the starting grid. No guessing, no arithmetic, nothing hidden. As the puzzles get harder, the chains get longer and the patterns get stranger: from a naked pair to an X-Wing to a Swordfish. That ladder is why sudoku holds up for years. Our page on whether you can solve sudoku without guessing explains why the answer is yes.

Many sudoku apps quietly weaken this. Auto-filled pencil marks remove the scanning, and a hint that simply fills in the digit removes the reasoning. The two apps below take the opposite approach.

Good Sudoku

Zach Gage's sudoku is built around technique. Its listing says a solver runs while you play, reads your answers and notes, and points you to the next technique you need. It spells out which techniques each difficulty requires, lets you practise them outside puzzles, and says its hardest puzzles need XYZ-Wings, Hidden Quadruples, Jellyfish and Swordfish. It also lets you import puzzles from elsewhere. It sells a Full Game Unlock for $4.99 and has no advertising label on its listing.

Sudoku Royale

Our app, so weigh this accordingly. Its listing states that every puzzle has exactly one solution. When you are stuck in Practice, a bulb lights up after about 90 seconds and tells you which cell to look at and which technique solves it, without giving the digit. An 88-level Journey teaches one technique per chapter up to XY-Wing, and the Dojo drills 15 groups of patterns on the clock. It is free, with no ads or purchases.

Two things a logic purist may miss: it has no auto-candidates (you write every pencil mark yourself, which some see as a feature) and no undo. It also checks every digit as you place it and rejects a wrong one, with no way to switch that off, so you cannot play a puzzle all the way to the end and find your own mistake.

Logic puzzles beyond classic sudoku

Nonogram.com

Nonograms reward the same habit as sudoku: find the square that can only be one thing. The numbers beside each row and column give the lengths of the shaded runs, and you work out every square from them. Easybrain's app has thousands of puzzles, daily challenges, tournaments and auto-crosses, per its listing. Extra lives after a mistake mean an error is not the end of a puzzle. It shows ads and sells Nonogram.com No Ads ($14.99) and coin packs.

Killer Sudoku by Sudoku.com

Classic sudoku plus cages with target sums. The logic gets richer because you reason about combinations (a two-cell cage that sums to 3 can only be 1 and 2) as well as positions. Free with ads, with Killer Sudoku No Ads for $14.99. The best killer sudoku apps page compares it with other killer apps.

Crossmath and Arcadia Zen Math

These are deduction puzzles in which the facts you deduce from are equations. You still look for the blank that can only take one value, but you get there by calculating. Crossmath sells Crossmath Premium $7.99, 4000 Coins $1.99 among other items. Arcadia Zen Math lists no in-app purchases, and its listing mentions an offline mode. If arithmetic is what you enjoy, see the best number puzzle games.

Popular puzzle games that are not pure logic

Nothing wrong with these; they are simply a different pleasure. Blockudoku and its cousins deal pieces at random, so a good run can end on a bad draw. In mahjong solitaire, tiles lower in the stack stay hidden until you clear what is above them, so a board can turn on a choice you could not have made with full information; Vita Mahjong softens that with free shuffles and undo. Brain Test and similar riddle games are lateral thinking: the answer is often hidden in the wording or in the picture itself. Fun with friends, not something you reason your way through step by step.

Where another app is the better pick

• You want the hardest techniques. Good Sudoku's listing names Jellyfish and XYZ-Wings. Sudoku Royale's lessons and drills stop at XY-Wing and Simple Colouring.
• You want to import puzzles from a book or newspaper. Good Sudoku has a Custom mode for that; Sudoku Royale does not.
• You want variety in one app. Neither sudoku app has variants. Pair one with Nonogram.com or a killer sudoku app.
• You want to check your own work. Sudoku Royale always checks digits as you place them.
• You are on Android. Sudoku Royale is iPhone and iPad only.

Our take

If you want a puzzle where effort, not luck, decides the result, pick one sudoku app and one nonogram app and you are covered. For the sudoku side, Sudoku Royale is free with no ads and Good Sudoku is a fair one-time price; our Sudoku Royale vs Good Sudoku page compares the two closely. See also games like sudoku and the full list on our sudoku app comparisons page.