About Grid Puzzles

Puzzles for all to enjoy.

Grid Puzzles is made by Infinite Loop Games. It is a collection of logic puzzles — the pencil-and-paper kind, where every answer follows from the clues in front of you and nothing depends on luck, reflexes, or trivia you happen to know. There are currently 8,300 puzzles across 19 games, and all of them are free to play.

We built this because the genre deserves better than it usually gets online. Logic puzzles are often published without anyone checking that they can be solved by reasoning at all, and graded by a difficulty label that someone assigned by feel. Both of those problems are fixable, so we fixed them.

Every puzzle has exactly one solution

This is the promise the whole site rests on. A logic puzzle with two valid answers is broken, because at some point it stops rewarding deduction and starts asking you to pick. A puzzle with none is worse. Either way you cannot tell from the outside, which means you spend your evening doubting yourself rather than the puzzle.

So nothing is published here until it has been proved unique. Every board is generated at random and then handed to a solver written specifically for that game, which searches for solutions and counts them. A candidate is kept only if the count is exactly one. Anything ambiguous or impossible is discarded before it is ever stored, and the great majority of generated candidates are discarded — that is the cost of the guarantee, and it is paid before you see the puzzle rather than after.

The same solver runs again when you finish a board. Your solution is checked against the rules of the game, not against our stored answer, which is why a puzzle can have several routes to the end and still be judged correctly. It is also why the answer never has to be sent to your browser to prove you solved something.

Difficulty is measured, not guessed

Every puzzle carries a difficulty — Easy, Medium, Hard, or Insane — and no human chose it. When the solver works through a new board it records how much of the solve was forced and how much required search: how often it ran out of certain moves and had to try a possibility, follow it, and rule it out. That figure becomes the puzzle’s score, and the score decides which difficulty it is filed under.

What this means in practice is that the labels describe the kind of thinking a puzzle demands rather than how long it takes. An Easy puzzle has a certain next move at every single point, from the first mark to the last — if you are stuck on one, something visible has been missed. An Insane puzzle contains at least one position where no move is certain and you have to reason ahead before the board gives way. A large Easy puzzle can take longer than a small Hard one, and that is the labels working correctly, not a mistake.

Because difficulty is emergent, we cannot make a puzzle hard on request. We generate, measure, and file the result where its score says it belongs.

How the site works

Every puzzle is free to play, and playing needs no account at all. Open any game, any size, any difficulty, solve the board, and nothing will interrupt you to ask who you are. There is no sign-up wall, no trial, and no daily limit.

An account is worth having anyway, because it lets the site remember you: puzzles you finish stay marked as finished, a completed board reopens on your solution rather than empty, and you can favourite the games you keep coming back to. It is free, and you are only asked about it once you have actually solved something. Either way your current board is kept in your own browser as you work, so an accidental reload or a closed tab does not throw it away.

There is an optional subscription for people who want more. It removes ads and it saves a part-finished puzzle to your account, so you can put a hard board down on one device and pick it up on another. Nothing is locked behind it — the entire catalogue is playable on a free account.

Each game has a How to Play guide with its full rules and a set of solving techniques with worked examples. If a game is new to you, that guide is the fastest way in — the techniques are the ones the solver itself uses, written out in plain language.

Playing comfortably

The boards work with a mouse, a touchscreen, or a keyboard. You can drag to fill a run of cells, undo and redo any number of moves, and pencil in a tentative mark as a note when you want to test an idea without committing to it. Notes are shown in their own colour so they never look like a mistake, and rows and columns light up as their conditions are met, so the board tells you where you stand without telling you the answer.

Nothing is timed. Nothing is scored. There is no streak to break.

Get in touch

If you have found a puzzle that seems wrong, spotted something broken, or want to suggest a game we have not built yet, we would like to hear it — reports of bad puzzles especially. Use the contact page and it will reach us.

Whether you have a few minutes or a quiet afternoon, we hope you find a puzzle you love.