Lights Out
Toggle cells and their neighbors until the whole five by five grid is dark.
Lights Out
Toggle cells and their neighbors until the whole five by five grid is dark.
Starts in your browser. Instructions are below.
Controls
- Keyboard and mouse
- Click a light to toggle it and the lights directly above, below, left and right of it.
- Touch
- Tap a light to toggle it and its neighbours.
Scoring and how to win
- The goal is to switch off all 25 lights on the 5 by 5 grid.
- The game counts your moves. Pressing the same light twice undoes it, so each light needs at most one press in a best solution.
- Every board is built by pressing random lights on a dark grid, so every puzzle can be solved.
How to play Lights Out
- 01Each tap flips the cell you pressed plus the cells directly above, below, left and right of it.
- 02Work out an order that switches everything off, the aim is an entirely dark grid.
- 03Use reset for a fresh, guaranteed solvable board.
About Lights Out
Lights Out is a puzzle in modular arithmetic disguised as a grid of buttons. Pressing a cell twice undoes itself, so only whether you press each cell matters, not the order, the whole puzzle reduces to solving a system of equations over two values.
A reliable technique is chasing the lights, press the cell directly below every lit cell working down the grid until only the bottom row is lit, then use a known set of top row presses to finish. Every board here is generated from a solved grid, so a solution always exists.
Frequently asked questions
- Is every board solvable?
- Yes. Boards are generated by applying random presses to a solved grid.
- Does the order of presses matter?
- No. Only the set of cells you press matters, because pressing a cell twice cancels out.
- What is the minimum number of moves?
- It varies by board, but a chasing the lights solution is usually close to optimal.
- How big is the grid?
- It is a five by five grid of 25 cells.
Related games and tools
Minesweeper
Use the number clues to work out where the mines are, and clear every safe square.
Sliding Puzzle
Slide numbered tiles into order on a 3x3 or 4x4 board, counting moves and time.
Sudoku
Fill the grid so every row, column and box contains the digits one to nine exactly once.
Four in a Row
Drop discs into the grid and line up four in a row against a thinking computer opponent.