Sliding Puzzle
NEWWorks on both desktop and mobile. Tap or click to play.
About This Game
The classic 15-puzzle, free online. Slide the numbered tiles into order in as few moves as possible. Choose 3x3, 4x4, or 5x5. Plays on mobile and desktop.
How to play Sliding Puzzle
Objective: Slide the numbered tiles until they read in order left to right, top to bottom, with the single empty gap resting in the bottom-right corner.
Pick a board size first with the buttons up top: 3x3, 4x4, or 5x5. The board arrives pre-shuffled, so there is no manual scramble step. Each board has one empty gap; a 4x4 holds tiles 1 through 15 plus that gap. You win the instant the numbers sit in order with the gap in the bottom-right cell. The opening layout is never dealt already solved.
Only a tile directly touching the gap can move. Those movable tiles are tinted purple and show a pointer cursor, so your legal options are always visible. Tap or click one and it slides into the gap, and the gap takes its old spot. There is no diagonal movement and no jumping over tiles. Every action is a single one-step slide of one tile into the empty space.
Arrow keys also work, and the direction is the way a tile travels. ArrowUp pulls the tile below the gap upward, ArrowDown pushes the tile above the gap down, ArrowLeft moves the tile right of the gap leftward, and ArrowRight moves the tile on the left rightward. If no tile sits in that direction, the key does nothing. Once you learn the four directions this is faster than tapping each tile.
The Moves counter climbs by one on every slide, and the Time clock starts on your first move, not before. There is no move limit, no timer pressure, and no way to lose. Your best result per board size is saved locally and shown as Best in moves. Use Shuffle / New Game to abandon a board for a fresh scramble, or Play Again from the win screen.
Tips and strategy
Rank by fewest moves
Your Best score is recorded by move count, not time, and only updates when you beat your prior move record for that size. Plan each slide instead of racing the clock; a slower 60-move solve beats a frantic 90-move one.
Solve top rows first
Lock in the top row and left column before touching the rest. Once tiles 1 through 4 are correct on a 4x4, never disturb them. That shrinks the puzzle to a smaller block below, which is easier to reason about.
Corner-pair the row ends
The last two tiles of a row are the hard part. Place the second-to-last tile into the final corner, park the last tile just below it, then rotate the pair in together. This avoids bumping a correct tile out to fit the other.
Read the purple hints
Only purple-tinted tiles can move on a given turn. Scan those two to four options and pick the one carrying a tile toward its home square, not the one nearest your cursor. The gap is your only tool, so aim it deliberately.
Start on 3x3
The 3x3 board has just eight tiles and teaches the corner-rotation trick without long detours. Master it, then step up to 4x4 and 5x5, where the same finish-the-frame method scales but each misplaced tile costs more correction slides.
The history of Sliding Puzzle
The sliding number puzzle descends from the 15 Puzzle, a four-by-four board of fifteen tiles that became a craze in the 1870s. It is often linked to Noyes Chapman, and the puzzlist Sam Loyd promoted a version and offered a prize for solving an impossible arrangement that mathematicians later proved could never be finished. That result showed exactly half of all tile arrangements are reachable from the solved state. This version scrambles only from a solved board using legal moves, so it sidesteps that trap and every deal here can genuinely be finished.
Frequently asked questions
How do I win?
Arrange the tiles in ascending order reading left to right and top to bottom, with the empty gap in the bottom-right corner. The moment the board reaches that exact arrangement, a Solved screen shows your board size, move count, and time. There is no partial credit or alternate win layout.
Can I lose a sliding puzzle or run out of time?
No. There is no lose condition, no lives, and no countdown. The clock only measures how long your solve took and starts on your first move. Take as many moves as you need; an unfinished board simply waits until you solve it or hit Shuffle for a new one.
How is the Best time and move record decided?
Best is tracked separately for each board size and ranked by fewest moves. A run replaces your record only when its move count is lower than your stored best for that size. The finishing time is saved alongside it but does not affect whether the record updates.
Is every shuffle solvable?
Yes. Boards are scrambled by a long chain of legal random slides from the solved state, so any position you see can be legally returned to solved. The shuffler also refuses to hand you a board that is already complete, so there is always work to do.