Free Online Number Slider
Slide numbered tiles into the correct sequential order by moving them into the empty space. Based on the classic 15-puzzle. Choose easy (3×3), medium (4×4), or hard (5×5) grid size. No download needed.
How to Play Number Slider
- The grid contains numbered tiles and one empty space.
- Click a tile adjacent to the empty space to slide it into that space.
- Rearrange all tiles into ascending numerical order (left to right, top to bottom) with the empty space in the bottom-right corner.
- Minimise your move count — a lower number of moves means a more efficient solve.
- Your move count and time are tracked as you play.
Difficulty Levels
- Easy — 3×3 grid (8-puzzle). 8 tiles to arrange; a manageable challenge for newcomers.
- Medium — 4×4 grid (15-puzzle). The classic format; requires planning several moves ahead.
- Hard — 5×5 grid (24-puzzle). A serious challenge demanding strategic sequencing.
Number Slider Tips & Strategy
- Solve the top row first, then the left column, working inward toward the bottom-right.
- Avoid disturbing already-solved tiles — route moves that keep completed sections intact.
- Use “cycle” moves to rotate tiles into position without breaking the rest of the grid.
- On the 4×4 grid, placing the last two tiles in a row requires a special three-move sequence — look it up to save frustration.
- Think two or three moves ahead rather than reacting move by move.
Frequently Asked Questions
- Is every shuffled puzzle solvable?
- Yes — the game only generates solvable starting positions. Approximately half of all random arrangements of the 15-puzzle are unsolvable, so we filter those out.
- What is the minimum number of moves to solve?
- The optimal number of moves varies by starting configuration and can be calculated using an A* algorithm. The game tracks your move count so you can try to improve.
- Can I play on a touch screen?
- Yes — tap any tile adjacent to the empty space to slide it.