CrispSudoku
Classic, Killer, Thermo & more
Free · Designed for iPad. Not verified for macOS.
Five Sudoku variants, six grid sizes, a daily challenge, and a built-in tutor that explains every move. No ads, no tracking, fully offline.
CrispSudoku is a polished, ad-free Sudoku game with real depth — five rule variants, six grid sizes, and a built-in tutor that explains how to solve every board.
PLAY YOUR WAY
• Five variants: Classic, Jigsaw (irregular regions), Sudoku-X (diagonals), Killer (summed cages) and Thermo (digits climb along each thermometer)
• Six grid sizes: 4×4, 6×6, 8×8, 9×9, 10×10 and 12×12
• Four difficulties, from Easy to Expert
• A new Daily Challenge every day — the same board for everyone
LEARN AS YOU PLAY
• "Explain the solve" walks through any board step by step, naming each technique (naked singles, hidden singles, locked candidates, X-wing and more)
• "Next logical step" hints tell you what to play next, and why
• Every puzzle gets an honest difficulty rating based on the hardest technique it actually requires
THOUGHTFUL TOUCHES
• Pencil-mark notes, unlimited undo, and live conflict highlighting
• A mistake limit that scales with difficulty
• Per-difficulty hint budgets, so hints stay meaningful
• Beautiful themes you unlock as you play
• Achievements, streaks and detailed statistics
PRIVATE BY DESIGN
• 100% offline — no account, no ads, no tracking, no data collection
• Every puzzle is guaranteed to have exactly one solution
CrispSudoku is free software, open source under the GNU AGPL-3.0.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Thermo Sudoku — a new variant.
Digits climb from each thermometer's bulb to its tip. Every size up to 9×9, and most boards need no starting digits at all: the thermometers alone are enough to pin the grid down.
Also in this update:
• A much bigger board on small and folding phones. On a compact screen the grid had been taking about half the width — it now fills it.
• Landscape is a real layout instead of a squeeze: the controls sit beside the board rather than above and below it.
• Everything holds together at large accessibility text sizes, in English and German.
• Explain the solve fits the screen it is on, so the whole board and the explanation are visible at once.
• Pencil marks are readable again on 10×10 and 12×12 boards.
• Killer puzzles now draw their cages correctly in every build.
• Fixed a startup problem that could leave the game showing a blank screen.
The developer, Christian Strobele, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Christian Strobele
- Size
- 20.6 MB
- Category
- Puzzle
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPad
Requires iPadOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Christian Ströbele
