Play 15-Puzzle Online — Free, No Download
Introduction
15-Puzzle is the sliding number puzzle that has been driving people quietly mad since the 1880s. Fifteen numbered tiles sit on a 4×4 board with one empty space, and your only move is to slide a tile into that space. Arrange the tiles in order from 1 to 15, left to right, top to bottom, and the puzzle is solved. It sounds simple, but the one-empty-space rule means every move undoes something else, and that tension is the whole game. Free in your browser, no download, and no timer — just you and fifteen stubborn tiles.
About 15-Puzzle
The 15-Puzzle was invented around 1880 — credit usually goes to Noyes Chapman, a postmaster in Canastota, New York — and it became the first true puzzle craze in American history. In 1891 the legendary puzzle designer Sam Loyd offered a $1,000 prize for solving a version with the 14 and 15 tiles swapped. Thousands tried. Nobody ever collected, because that particular arrangement is mathematically impossible to solve.
The rules fit in one sentence: slide tiles into the empty space until the numbers run 1 to 15 in order, left to right, top to bottom. What makes it hard is that the empty space gives you exactly one degree of freedom. Every move that fixes a tile usually disturbs one you already placed, so solving means building and protecting structure rather than blindly nudging tiles toward their spots.
This version is a clean, dependency-free JavaScript implementation by Arnis Ritiņš, released under the MIT license. It shuffles the board by making 100 random legal moves from the solved position, which guarantees every puzzle it serves you is solvable — a real mercy, because half of all random 15-Puzzle arrangements are dead ends. There is no timer and no move counter, just the board, a Scramble button and a Solve button.
How to Play 15-Puzzle
Look at the target order.
The finished board runs 1 to 4 across the top row, 5 to 8 on the second row, 9 to 12 on the third row, and 13, 14, 15 with the empty space on the bottom row. That is the picture you are working toward.
Move a tile into the empty space.
Click or tap any numbered tile that sits directly next to the gap — up, down, left or right. The tile slides into the empty space, and the gap moves to where that tile was.
Repeat, one move at a time.
You can never pick up a tile or swap two tiles directly. The empty space is your only tool, so every solution is a path you walk with that one gap, one click at a time.
Finish the last row.
The puzzle is solved when the numbers run 1 to 15 in order and the empty space sits in the bottom-right corner. A confirmation message then asks whether you want to scramble a fresh board.
Scramble for a new challenge.
Click Scramble to shuffle the board with 100 random legal moves, or Solve to reset it to the finished position and start over. Every scrambled board is guaranteed solvable.
15-Puzzle Controls
| Action | Desktop | Mobile |
|---|---|---|
| Move a tile into the empty space | Click the tile next to the gap | Tap the tile next to the gap |
| Move a tile up | Click the tile directly below the gap | Tap the tile directly below the gap |
| Move a tile down | Click the tile directly above the gap | Tap the tile directly above the gap |
| Move a tile left | Click the tile directly right of the gap | Tap the tile directly right of the gap |
| Move a tile right | Click the tile directly left of the gap | Tap the tile directly left of the gap |
| Move with arrow keys | Not available — this build is click and touch only | Not available — use taps |
| Scramble into a new puzzle | Click the Scramble button | Tap the Scramble button |
| Reset to the solved board | Click the Solve button | Tap the Solve button |
| Undo the last move | Not available — use Solve to start over, or plan more carefully | Not available |
| Fullscreen | Use your browser's zoom or fullscreen controls | Use your browser's zoom or fullscreen controls |
15-Puzzle Tips & Strategies
Solve the top row first
Start with 1, 2, 3, 4 across the top, left to right. Once a row is complete, never touch those tiles again — treat them as fixed furniture. Most solvers lock in the first two rows before working on the bottom half.
Think of the gap as your mover
The empty space is not a hole to fill; it is the hand that does all the work. Every move slides a tile into it, so plan where you want the gap to go next, not just which tile to click.
Rotate three tiles to reposition one
When a tile is close to its spot but blocked, loop three tiles around the gap in a small circle. This classic trick slides one tile into place while the other two come back to their own starting positions.
Leave the bottom two rows for last
Solving the first two rows locks in half the board. For the final rows, place 13 first, then work 14 and 15 together as a pair rather than one at a time — finishing the last row tile by tile is how solvers get stuck.
Move the gap along a path, not randomly
Beginners click whichever tile happens to sit near the gap. Strong players move the gap along deliberate routes — around a tile, under a tile — so each click advances a plan instead of rearranging the mess.
If you get stuck, Scramble and start fresh
There is no penalty for a new board. Because this version shuffles with 100 legal moves, every scramble is solvable, so starting over is a strategy, not a surrender.
What makes 15-Puzzle worth playing
- Classic 15-Puzzle on a 4×4 board with fifteen numbered tiles
- Runs entirely in your browser with no download or plugin
- Guaranteed solvable — every shuffle uses 100 random legal moves
- No timer and no move counter, so you can solve at your own pace
- Works with mouse clicks on desktop and taps on phones and tablets
- Open source under the MIT licence with credit to the original developer
Game Info
| Developer | Arnis Ritiņš |
|---|---|
| Released | 2015 |
| Genre | Puzzle, Number, Sliding |
| Players | Single player |
| Technology | HTML5 / JavaScript |
| Platforms | Desktop, Tablet, Mobile browser |
| Average session | About 8 minutes |
| Licence | MIT |
| Last updated |
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15-Puzzle — Frequently Asked Questions
What is the 15-Puzzle?
The 15-Puzzle is a 4×4 sliding puzzle with fifteen numbered tiles and one empty space. The goal is to slide the tiles so the numbers run 1 to 15 in order, with the empty space in the bottom-right corner.
Is every 15-Puzzle arrangement solvable?
No. Only half of all arrangements can be solved — the rest are mathematically impossible, a quirk known as the parity of the puzzle. This version avoids the trap by shuffling with 100 random legal moves from the solved board, so every puzzle it gives you is solvable.
What is the parity rule in the 15-Puzzle?
The parity rule says a board is solvable only when the number of inversions and the row position of the empty space match in a specific way. The famous 14-15 puzzle, which offered a $1,000 prize in 1891, is unsolvable precisely because it breaks this rule.
How should I use the empty space?
Treat the empty space as your mover, not a hole to fill. Every move slides a tile into it, so you control the board by controlling where the gap goes. Move the gap next to a tile, then slide the tile in.
Is there a timer or a move counter?
No. This version has no timer and no move counter — you solve at your own pace with no pressure. That makes it a genuinely relaxing puzzle rather than a speed test.
Is the 15-Puzzle free to play?
Yes, completely. The game is open source under the MIT licence and free to play here with no payment, no sign-up and no premium version.
Can I play the 15-Puzzle on my phone?
Yes. Tap a tile next to the empty space and it slides into the gap. The game works in portrait and landscape on mobile browsers.
Licence & Attribution
15-Puzzle by Arnis Ritiņš · MIT License
Art and audio: Same as code license — plain HTML/CSS/JavaScript with no third-party assets
Licence verified .