Fifteen Puzzle
Put the numbered tiles in order on a 4×4 board, with the empty space at the lower-right corner. Move one neighboring tile at a time to make room.
About Fifteen Puzzle
The Fifteen Puzzle is a sliding number puzzle on a 4×4 board. Arrange tiles 1–15 in order and leave the blank at the lower-right corner.
This version has 99 original boards: Warm-up (1–18, 18 boards), Practice (19–54, 36), and Challenge (55–99, 45). Later groups place tiles farther from their goal positions overall, while solving still depends on planning the blank’s route. It tracks moves and time, supports Undo, and does not save a run between visits.
How to play Fifteen Puzzle
- 01Arrange the tiles from 1 to 15 in reading order, leaving the empty space in the lower-right cell.
- 02Move only a tile that shares an edge with the empty space. Diagonal tiles, distant tiles, and tiles across a row boundary cannot move; each move shifts just one numbered tile.
- 03A valid tile move adds one to the move count. The timer starts with the first valid move, pauses while the page is hidden, and resumes when you return.
- 04Choose among 99 original boards: Warm-up covers 1–18 (18 boards), Practice 19–54 (36), and Challenge 55–99 (45). In later groups, tiles sit farther from their goal positions overall, so you still need to plan the blank’s route. The group names do not promise a shortest solution or rank subjective difficulty.
- 05Undo restores up to 1,024 recent moves and keeps elapsed time, including when you undo a solved board. Restart or choose a puzzle to reset its move count and timer. After a win, the next puzzle starts automatically in three seconds; choose Continue now or Stay here. Puzzle 99 stays on screen.
- 06Focus the board and use the arrow keys or W/A/S/D to move the empty space. You can also use the direction buttons or tap a tile next to the empty space. R restarts and Z undoes while the board is focused.
Fifteen Puzzle controls
- Keyboard
- Focus the board, then use the arrow keys or W/A/S/D to move the blank in that direction. R restarts the current puzzle and Z undoes a move. These shortcuts work only while the board is focused.
- Touch and direction buttons
- Tap a numbered tile directly next to the blank to slide that one tile. The four direction buttons also move the blank; tapping a distant tile does nothing.
- Puzzle controls
- Choose one of the 99 numbered puzzles, restart the current one, or undo up to 1,024 recent moves. After solving, the next puzzle starts in three seconds unless you choose Stay here; Continue now skips the wait. Puzzle 99 stays on screen. Restarting or choosing a puzzle resets its move count and timer.
Fifteen Puzzle: levels and progress
Warm-up has 18 puzzles (1–18), Practice has 36 (19–54), and Challenge has 45 (55–99). In the later groups, tiles sit farther from their goal positions overall, so plan the blank’s route as well. The group names do not promise a shortest solution or rank subjective difficulty.
The timer begins with the first valid move. It pauses when the page is hidden and resumes when you return. Undo retains elapsed time; restart and puzzle selection clear it.
Fifteen Puzzle tips and strategies
Keep a route open
A tile can only enter the blank from one neighboring cell. Plan a route for the blank as well as a destination for each tile.
Work in sections
Arrange part of the target order while leaving room to move tiles that are still out of place. Closing a row too soon can limit access to lower cells.
Watch the blank’s position
Each move swaps the blank with one adjacent tile. Think about where the blank will be after the slide and which neighboring tile becomes available next.
- Plan a tile’s route to its destination, not just its next move. The empty space must travel around the board to bring a tile into place.
- Build an ordered section while keeping enough room to move the remaining tiles. Locking a row too early can make the last few pieces harder to position.
- Use Undo to compare a recent choice. Undo keeps the timer running and can restore the board after a solved puzzle.
Fifteen Puzzle FAQ
Can I slide a whole row of tiles at once?
No. One move shifts one tile that is directly above, below, left, or right of the empty space.
What do Warm-up, Practice, and Challenge mean?
Warm-up covers puzzles 1–18 (18 boards), Practice 19–54 (36), and Challenge 55–99 (45). Later groups place tiles farther from their goal positions overall, but you still need to plan the blank’s route; the names do not rank subjective difficulty.
When does the timer run?
It starts after your first valid move, pauses while the page is hidden, and resumes when the page is visible again. Undo keeps elapsed time; restarting or selecting a puzzle resets it.
Are puzzles saved between visits?
There is no cross-visit save, best-time table, or random level generator. The play timer has no deadline; after a win, the next puzzle starts in three seconds unless you choose Stay here. Continue now skips the wait.
Can I move a tile that is not next to the blank?
No. The tile must share an edge with the blank; diagonal and multi-cell moves are not allowed.
What happens to the timer when I hide the page?
It pauses while the page is hidden and resumes when the page becomes visible. Undo keeps the elapsed time; restart or selecting a puzzle resets it.
Does the game remember my board later?
No. The current puzzle is not saved between visits, and there is no best-time table. The play timer has no deadline; after a win, the next puzzle starts in three seconds unless you choose Stay here. Continue now skips the wait.