Sudoku Solver
Enter a puzzle and solve it outright, or step through it one logical deduction at a time — with the technique explained each step.
Click a cell and type a digit, or tap the number pad. Then Solve, or ask for a Hint.
Solve it, or learn to solve it
Press Solve for the full answer, or Hint to fill just the next forced cell and see why it has to be that digit. The solver checks that your puzzle is valid and has a single solution first — no solution or several, and it tells you instead of guessing. Prefer to play? Try the daily puzzle.
Frequently asked questions
How do I enter a puzzle?
Click any cell and type its digit, or tap the on-screen number pad. Enter all the givens from your puzzle, leaving the rest blank, then press Solve. Arrow keys move between cells.
What if it says 'more than one solution'?
A proper Sudoku has exactly one answer. If the solver finds several, the puzzle you entered is under-constrained — double-check you copied every given, since a missing digit usually causes this.
Does the hint just tell me the answer?
It reveals one cell at a time and names the reason: a 'naked single' (only one digit fits that cell) or a 'hidden single' (a digit that fits only one cell in a row, column, or box). It's the honest way to get unstuck without spoiling the whole grid.