Lights Out Solver
Stuck on Lights Out, or a tile flip or light switch puzzle in a game? Tap in the lit tiles and see exactly which ones to press. Free, right in your browser.
Tap a tile to switch it on or off (with a mouse you can drag across tiles). Mostly lit? Press Flip all first. Match your puzzle, then press Solve.
Three states: tap a tile once for amber, twice for blue. Off is the color your game wants every tile to end on; amber is one press past it, blue is two.
What happens when you press one? (press pattern and options)
Press one tile in your game and check which tiles change. Pick the picture that matches; the outlined square is the tile you pressed.
Tap squares to set which tiles a press changes. The outlined square is the tile you press.
How the solver works
In Lights Out, pressing a tile flips it and its neighbors. Two things make it solvable by math instead of guesswork: the order you press in doesn’t matter, and pressing a tile twice undoes it. So a solution is just a set of tiles, each pressed once. The solver writes the board as a set of equations, one per tile, and solves them all at once. On any board up to 12×12 that takes a blink.
If a board has more than one solution, it shows the shortest. If a board has no solution at all, it tells you, and suggests the closest boards that do work, because a no-solution board usually means one tile got entered wrong.
Solving it by hand: light chasing
- For every lit tile in the top row, press the tile directly below it. The top row goes dark.
- Do the same for the second row, then the third, all the way down. Now only the bottom row can have lights left.
- Look up the leftover bottom row in the table for your size (5×5, 3×3), press the top-row tiles it gives you, and chase the lights down again. The board goes dark.
On a 4×4 board you can skip the table: if the board can be solved, chasing alone clears it.
The full walkthrough, with a real board solved step by step: How to Solve Lights Out (the Trick That Always Works).
The classic sizes at a glance
| Size | Solvable boards | Solutions each | Most presses needed |
|---|---|---|---|
| 3×3 | all | 1 | 9 |
| 4×4 | 1 in 16 boards | 16 | 7 |
| 5×5 | 1 in 4 boards | 4 | 15 |
| 6×6 | all | 1 | 36 |
| 7×7 | all | 1 | 49 |
Other sizes: 3×3 · 4×4 · 5×5 · 6×6 · 7×7
💡 Want to play one instead? Porchlight is a free daily lights puzzle: one new board every day. ↗Questions
How do I use the solver?
Pick your grid size, tap each tile that’s lit in your puzzle, then press Solve. The tiles to press get a red dot. Press them in any order and the board goes dark. If you’d rather go one at a time, use Walk me through it.
Does the order of presses matter?
No. In Lights Out every press just flips the same tiles no matter when you do it, so any order works. Pressing the same tile twice cancels itself out, which is why a solution is just a set of tiles.
It says my board can’t be solved. Now what?
Some boards really have no solution (on a 5×5 grid, 3 out of 4 random boards don’t). More often a tile was entered wrong, so the solver suggests boards one tile away that do work. Also check that your game’s press pattern matches: press one tile in your game and compare it with the pictures under “What happens when you press one?”
My puzzle is called a tile flip puzzle, or a light switch puzzle.
Same puzzle, different name. Tile flip, light switch, flip switch and light flip puzzles all work the same way: pressing a tile flips it and some of its neighbors. Set the press pattern to match and the solver handles it.
My game wants every light on, not off.
Enter your board as it is, press Flip all, then Solve. The same presses that turn the flipped board dark turn your real board fully lit. (That works for on/off puzzles; for three colors, see the next question.)
My game’s tiles cycle through three colors.
Turn on “Three states”. Off stands for the color you’re trying to reach. For every other tile, tap it once for each press your game would need to go from the goal color to that tile’s color: amber is one step past the goal, blue is two. The solver may tell you to press a tile twice (marked ×2).
Can it do sizes that aren’t square?
Yes. Use the custom size boxes for anything from 1 to 12 rows and columns, like 4×8 or 3×4.
Does anything get sent to a server?
Your board never leaves your browser; the solving happens right on the page. The site uses Google Analytics (in Europe it asks first) to count visits and which features get used, like the grid size, but never the board itself. A shared link carries the board in the part after the #.