Kipi WordsFree Sudoku Solver
Stuck on a Sudoku? Type or tap in the numbers from your puzzle and get the complete solution in a blink — or take one hint at a time and keep playing. Works on easy, medium, hard, and evil puzzles.
Sudoku Solver
Tap a square, then tap a number (or use your keyboard) to enter the numbers already printed in your puzzle. Then hit Solve. Numbers you enter are black, the solution appears in blue, and hints appear in green.
Enter your puzzle, or load an example to see how it works.
How to use this Sudoku solver
- Enter the printed numbers. Tap any square, then tap a number on the pad (or type it). These become the black "given" numbers of your puzzle. Tap a filled square and press the red ✕ to erase a mistake.
- Watch for red squares. If the same number appears twice in a row, column, or 3×3 box, the clashing squares turn red as you type — fix those before solving.
- Press Solve for the complete finished grid in blue, or Hint to fill just one square in green and keep playing yourself.
- Press Check any time to confirm your entries have no conflicts and the puzzle can still be completed.
How Sudoku works
Every Sudoku grid is 9 rows, 9 columns, and nine 3×3 boxes. The only rule: each row, column, and box must end up containing the numbers 1 through 9 exactly once. Nothing is added, multiplied, or guessed — a proper Sudoku always solves with logic alone, and a well-made one has exactly one solution. This solver applies those same rules thousands of times a second until the grid is full, which is why it can finish an evil-level puzzle as easily as an easy one.
Solving tips, if you'd rather finish it yourself
- Scan for near-full lines. A row or box with 7 or 8 numbers usually gives up its missing numbers fast — check which numbers are absent, then eliminate squares where they can't go.
- Work one number at a time. Pick a number, say 7, and look at the rows, columns, and boxes that already have one. The crossings often leave only one square where a 7 can live.
- Use pencil marks. Lightly note the 2–3 candidates in tricky squares. Pairs of squares in a line holding the same two candidates ("naked pairs") clear those numbers from every other square in the line.
- Stuck for real? Take one green hint above, then keep going on your own — one square is often all it takes to unlock the rest.
Common questions
Is this Sudoku solver free?
Yes. The solver is completely free, works right in your browser, and needs no signup or download. Enter as many puzzles as you like.
Can it solve hard and evil Sudoku puzzles?
Yes. The solver uses the rules of Sudoku itself — every row, column, and 3x3 box must contain the numbers 1 to 9 exactly once — so it can complete any valid puzzle, from easy newspaper grids to evil-level ones, as long as the numbers entered are correct.
Why does it say my puzzle has no solution?
Almost always a typo: one wrong number copied from the paper or app makes the whole grid impossible. Check the highlighted conflicts first, then compare each row against your original puzzle. If two numbers clash in a row, column, or box, the grid turns them red as you type.
What does 'more than one solution' mean?
A well-made Sudoku has exactly one solution. If the numbers entered so far allow several completions, the solver still shows you one full solution and tells you there are others. That usually means a given number is missing — check whether you left a square blank that should be filled.
Can I get a hint without solving the whole puzzle?
Yes. Tap Hint and the solver fills in exactly one square (shown in green) and tells you where it went, so you can keep playing from there. Use Check any time to confirm your grid has no conflicts and can still be solved.