15 Puzzle Solver & Sliding Puzzle

Enter a real 8, 15 or 24 puzzle and see how to put it back in order, move by move, or play a sliding puzzle with numbers or your own photo.

How to use

1. Under "Solve my puzzle", read your puzzle row by row from the top left and tap the same numbers, with "Empty" for the empty square.
2. Press "Solve" for every move, or "Hint: next move only" for one move at a time.
3. Step through the board with "Play", "Next" and "Previous"; each move reads like "Move tile 7 to the left".
4. Under "Play", slide tiles into the empty square and press "Solve from here" if you get stuck.

How it works

• If the tile-order parity (on even widths counted with the row of the empty square) differs from the finished puzzle, the arrangement cannot be solved; usually two tiles were swapped when it was reassembled, and the page names two to swap.
• 3 × 3 and 4 × 4 boards are solved in the fewest moves (A* and IDA* search with pattern databases). If a 4 × 4 search takes too long on the device, a quicker solution is shown and marked as not the shortest; 5 × 5 and 6 × 6 boards are solved row by row.
• One move is one tile sliding one square.
• Everything runs in this browser; arrangements, photos and records stay on this device.

Questions and answers

How do I solve a 15 puzzle I cannot finish?

Choose "Solve my puzzle" and 4 × 4, enter the numbers as they are on your puzzle and press "Solve".

Why can my 15 puzzle not be solved?

Only half of all arrangements can be reached by sliding. If two tiles, such as 14 and 15, were swapped when the puzzle was reassembled, swap them back by hand.

What is the most moves a 15 puzzle needs?

At most 80 moves, and an 8 puzzle at most 31. Most shuffled 15 puzzles need 40 to 65 moves.