Lights Out
Turn off all the lights - but tapping one toggles its neighbours too. Pure logic puzzle in 5×5 or 6×6.
Turn off all the lights - but tapping one toggles its neighbours too. Pure logic puzzle in 5×5 or 6×6.
This free Lights Out from KX Toolkit is part of our all-in-one online toolkit. It runs entirely in your browser, so your data never leaves your device for client-side operations. 100% free, forever - no paywall, no credit card, no trial.
How to use the Lights Out
- Open the tool - you are already here, nothing to install.
- Enter your input in the form above.
- Click the action button to run the tool. Results appear instantly.
- Copy the result to your clipboard, or download it as a file.
What you can do with the Lights Out
- Speed up daily work without juggling multiple websites.
- Run quick checks before publishing or sending.
- Verify or transform data without writing any code.
- Free alternative to paid desktop or SaaS tools.
Why use KX Toolkit's Lights Out
- Browser-based: Works on Windows, macOS, Linux, iOS and Android - no install, no extension.
- Privacy-first: Client-side tools never upload your data; server-side tools delete files right after processing.
- Mobile-friendly: Full feature parity on phones and tablets - not a stripped-down view.
- Fast: Optimised for instant feedback. No artificial waiting screens, no email-gated downloads.
- One hub for everything: 300+ tools across SEO, text, image, PDF, code, color, calculators and more - skip switching between sites.
Tips for the best results
For best results, keep your input as clean as possible - remove extra whitespace or formatting before running the tool.
Related Browser Games
If you find this tool useful, explore the full Browser Games collection or browse our complete tool directory. KX Toolkit is built for marketers, developers, designers, students and anyone who needs a quick utility without signing up for yet another SaaS.
How do I play Lights Out?
You start with a grid of lit and unlit squares. Click any square to toggle its state, but doing so also toggles the squares directly above, below, left and right of it. Your goal is to turn every light off. The puzzle sounds simple but the chain reaction means almost every move undoes part of your previous progress.
What grid sizes are available?
The default is a 5x5 grid, which is the classic Lights Out puzzle. Smaller 3x3 and 4x4 grids are available for an easier introduction, and a 7x7 grid is offered for serious puzzlers. Every size is solvable from any random starting state on the 5x5, but on other sizes some random starts can be unsolvable, so the game ensures a valid puzzle.
What is the trick to solving it?
Use the chase the lights method. Look at the top row, and for every lit square in that row, click the square directly below it. After processing the top row, repeat with the second row, and so on. Once you reach the bottom, the top row will tell you which columns to start in to finish the bottom cleanly.
Is every starting state solvable?
On the standard 5x5 board every random arrangement is solvable, which is one of the nice mathematical properties of the puzzle. On other sizes, some configurations are unsolvable, so the game generates only valid puzzles on those grids. If you ever get stuck, the New Puzzle button will give you a fresh, guaranteed-solvable starting state.
Are best scores tracked?
Yes. The fewest moves used to solve each grid size is stored in browser local storage. A move counter ticks up on every click, and beating your previous best triggers a celebration. The optimal solution for the standard 5x5 is at most 15 moves, so see how close you can get to that mathematical lower bound.
Does it work on phones?
Yes. Each cell is sized for comfortable tapping, and the larger grids zoom out to fit smaller screens without cropping. There are no swipes or gestures to learn, just tap squares to toggle them. Phones in portrait mode work well even for the 7x7 grid, although a tablet gives you a bit more room to think and plan.
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