Using the solvers
Every solver on Puzzle Solvers works the same way: you build the puzzle, it checks it, then it solves it one step at a time and tells you why each step is true. It is a tutor, not an answer key.
The three steps
- Build — choose the grid size and enter the puzzle as printed: givens, cages and totals, clues, signs or pearls.
- Check — the solver confirms the puzzle is complete and solvable, and points out anything that is missing or contradictory.
- Solve — step forward one deduction at a time. Each step highlights the cells involved and explains the reasoning in plain English. Jump to the end whenever you like.
From a game to the solver — and to Slate
Inside most games, Send to Solver opens the same puzzle in the matching solver, ready to step through. Send to Slate opens it as a board on the Slate classroom whiteboard, where a teacher can solve it in front of a class with ordinary pen marks.
The solvers
- Sudoku SolverType or paste the puzzle — use Import puzzle string for an 81-character line of digits and dots.
- Killer Sudoku Solver① Build puzzle: click cells to group them into a cage, then type the cage total. Load the sample to see how it
- Calcudoku Solver① Build puzzle: choose the grid size, select cells to make a cage, then set its operation and target.
- Kakuro Solver① Build: click cells to toggle black and white. Click a black cell next to white cells to enter its across and
- Futoshiki Solver① Build: choose the grid size, click cells to enter the given numbers, and click the gap between two cells to
- Hitori SolverChoose a grid size and type the numbers from your puzzle (or press Random).
- Nurikabe SolverChoose a grid size and enter the island numbers in their cells; leave every other cell blank (or press Sample)
- Pearl Path SolverPick White or Black and click cells to place pearls; click a pearl to cycle it (white → black → empty).
- Number Snake Solver① Build: choose the variant and grid size, then type the given numbers.
- Magic Sum Solver① Build: choose the grid shape, enter row and column targets in the blue cells and any known values.
- Skyscrapers SolverChoose the grid size, click each clue around the edge and type its number; type any given heights into their s
- Binary Puzzle SolverChoose the grid size and tap squares to copy in your puzzle (empty → 0 → 1), or press Sample.
- Star Battle SolverChoose the stars per line and the grid size, then paint each region: pick a colour swatch and drag over its sq
- Rectangles SolverChoose the number of rows and columns, then click each numbered square and type its number (or press Sample).
- Bridges SolverChoose the size and whether up to two bridges or one may join a pair, then click each island’s square and type
- Nonogram SolverChoose the rows and columns, click each clue area and type its blocks, or draw a picture and let the clues fol
- Tents SolverChoose the size, click each tree’s square, then click each count and type it (or press Sample).
- Light Up SolverChoose the size, then click squares to make walls and type their numbers (or press Sample).
- Kakurasu SolverChoose the size, then click each total and type it (or press Sample).
- Slitherlink SolverChoose the size, click each numbered square and type its number (or press Sample).
- Galaxies SolverChoose the size and click where each dot is (or press Sample). Click a dot again to remove it.
- Sun & Moon SolverChoose the size and rules, then enter the given suns, moons and signs (or press Sample).
- Sudoku Variants SolverChoose the variant and size, then enter the givens and the variant clues (or press Sample).
- Number Path SolverChoose the size, enter the numbers and walls (or press Sample).
- Sum Circles SolverChoose the version, type each circle total (and colour total) and any given numbers — or press Sample.
- Equation Square SolverChoose left-to-right or BODMAS working, set the twelve signs and six answers, and add any given numbers — or p
- Number Chain SolverType the chain — steps can be +7, −12, ×3, ÷4, double, half, square, root, cube, 25% (of), +10% (increase) or
- Number Blocks SolverChoose the size, draw the blocks (or press Sample), then type the given numbers.
- Letter Sums SolverType one or more sums using + − × and = (up to 10 different letters).
- Make the Number SolverChoose how many numbers and whether every number must be used, then enter the numbers and the target (or press
- Number Regions SolverChoose the size, type the given numbers (or press Sample).
- Ripple Rooms SolverChoose the size, draw the rooms (or press Sample), then type the given numbers.
- Sightlines SolverChoose the size and type the numbers (or press Sample).
- Fleet Finder SolverChoose the grid and fleet, type the counts and mark any given water or ship squares (or press Sample).
- Mosaic SolverType the numbers of your puzzle (or press Sample).
- Domino Hunt SolverChoose the domino set and type the grid (or press Sample).
- Number Pyramid SolverType the bricks you know (or press Sample).
- Cross Numbers SolverSend a puzzle from the game, or press Sample.
- Thermometers SolverChoose the size, draw each thermometer from bulb to tip and type the counts (or press Sample).
- Water Tanks SolverChoose the size, draw each tank and type the counts (or press Sample).
- Magnets SolverChoose the size, draw the plates and type the counts (or press Sample).
- Edge Letters SolverChoose the grid and letter set and type the edge letters (or press Sample).
- Four Colours SolverChoose the size, draw the regions and add the given colours (or press Sample).
- Mirror Maze SolverChoose the size, place the mirrors, and type the numbers and totals (or press Sample).
- Light Switch SolverChoose the board size and switch shape, and click to set the lights (or press Sample).
- Train Tracks SolverChoose the size, type the counts, set A and B, and add given pieces (or press Sample).
- Pipe Link SolverChoose the board size and enter every piece (or press Sample).
- Straights SolverChoose the size, mark the black squares and type the numbers (or press Sample).
- Domino Shade SolverChoose the size and draw the regions (or press Sample).
- Tetro Shade SolverChoose the size and draw the regions (or press Sample).
- Room Shade SolverChoose the size, draw the rooms and type the numbers (or press Sample).
- Arrow Loop SolverChoose the size and enter the arrow clues (or press Sample).
- Sliding Tiles SolverChoose 3×3 or 4×4 and set up your position (or press Sample).
The calculators
The cage and run calculators do one job fast: list every combination that fits a cage or run, filter out digits you have placed, and point out digits that must (or cannot) appear. Use them alongside a puzzle on paper.
Questions
Do the solvers just give the answer?
No — each solver works one deduction at a time and explains it, so you can follow the logic or stop at any step and carry on yourself.
Can I enter a puzzle from a newspaper or app?
Yes. Every solver starts in Build mode where you type or click in the puzzle exactly as printed.
What does Send to Solver do?
Inside a game, it opens the same puzzle in the matching solver, already built — useful when you are stuck.
What does Send to Slate do?
It opens the puzzle as a board on the free Slate whiteboard, so a teacher can solve it with a class using ordinary pen marks.
Is there a cost or sign-up?
No. Everything on Puzzle Solvers is free and runs in your browser with no account.