How to Play the 15-Puzzle

The 15-Puzzle is a classic sliding tile game played on a 4×4 grid. Fifteen numbered tiles fill the board, leaving one empty space. Slide tiles into the empty space to rearrange them until every tile is in order from 1 to 15.

The Goal

Arrange all 15 tiles in ascending order — left to right, top to bottom — with the empty space in the bottom-right corner. The solved position looks like this: 1, 2, 3, 4 across the top row, then 5, 6, 7, 8, then 9, 10, 11, 12, then 13, 14, 15 and the blank.

Your score is a combination of how many moves you used and how fast you solved it. Fewer moves and less time means a better leaderboard ranking.

Controls

• Click a tile adjacent to the empty space to slide it in.
• Click a tile further away in the same row or column and the entire line of tiles between it and the empty space slides together in one move — just like a real physical puzzle.
• Arrow keys move a tile into the empty space from the corresponding direction.

• Tap a tile adjacent to the empty space to slide it in.
• Tap a tile further away in the same row or column and the whole row or column slides in one move.

Use the New Game button to reset the board and start over at any time.

Example: Solving Step by Step

The screenshots below show a photo puzzle being solved using Lady Di's Mines as the image. Each tile carries a number and a fragment of the picture — so you can use the image as a visual guide while you solve.

The starting position. Tiles are randomised but always solvable. The empty space (dark square) can be anywhere on the board.

Midway through. The top rows are falling into place. Focus on completing one row at a time from the top down.

Nearly finished. Only the bottom rows remain scrambled. At this stage small adjustments are needed — avoid undoing progress in rows already solved.

Solved! All tiles are in order and the full image is revealed. Your time and move count are recorded for the leaderboard.

Photo Puzzle Modes

The daily puzzle and custom photo puzzles offer two different visual modes:

• Tiles mode — each tile shows its slice of the photo. The image gives you visual context to guide your solving — use the picture as a second layer of information on top of the numbers.
• Reveal on win — tiles show only numbers while you solve. When you place the last tile correctly, the full photo is revealed underneath. The image is a reward for finishing, not a hint.

Strategy

Solve row by row from the top. Rows 1 and 2 can each be completed and locked in place without disturbing anything above. The final two rows (tiles 9–15) are solved together using a rotation technique.

Place tile 1 and tile 2 together. Trying to slide tile 1 into position by itself often displaces tile 2. Instead, manoeuvre both tiles 1 and 2 into their correct column positions simultaneously, then rotate them into the top row at the same time.

Use multi-tile slides. Clicking or tapping a tile that is not directly adjacent to the empty space slides the whole intervening row or column. This is faster than moving tiles one at a time and is essential for efficient solving.

Count your moves. Every slide counts as one move, including multi-tile slides. A single well-planned multi-tile slide can save several single-tile moves — plan ahead to minimise your count.

Daily Puzzle

A new puzzle is generated every day at midnight UTC — the same scrambled board for every player worldwide. Solve it, submit your score, and see how you rank on the leaderboard.

You can also create your own photo puzzle using the Puzzle Generator — upload any image, choose your mode, and share the link with anyone.