Sudoku Solver

To place the numbers/letters so there is only one in each row, column and square group. Built in are 9*9 puzzles, using the numbers 1..9 and 16*16, using 0..9,A..F.

Select the puzzle and press SolveIt and a solution is found. Press ShowMoves to see how it does it - using backtracking - where a number is found for the next square, and then the next square is tried. If it cant find a number in the next place the current number must be wrong, so the program looks for another number.

Or you can solve it interactively. Click on a square and you are told which numbers can go there - enter one. Or press FindMissing and the program will automatically fill in a square if it realises all other numbers are in the same row/column square. Or press Find One Only where the program will determine if only one number can go in a square. ShowAvail shows all the numbers which can go in each square.