Welcome to the world's largest web site devoted to logic puzzles! We've got more than 25,000 unique puzzles available for play, both online and the old fashioned way - with pencil and paper.

Dec 12, 2025 · Puzzles with larger grid sizes and higher difficulty levels will have a larger maximum number of points. To increase the point potential, select a greater grid size or difficulty level (or both).

Dec 12, 2025 · Get ready to solve! A brand new 4 x 5 puzzle has been initiated and is ready for you to begin whenever you're ready. The timer will begin the moment you click the "Start This Puzzle" …

Whether you know them as Calcudoku, Mathdoku or KenKen (TM), we've got thousands of unique puzzles for you to solve, ranging from the easiest 4x4 to the most difficult 9x9.

If you're new to grid-based logic puzzles, this tutorial will teach you the basics. Start with the "Introduction" first, then move on to the tutorials discussing specific clues or solving methods.

Two hundred more logic puzzles, complete with stats, solutions and difficulty ratings. Each puzzle is provided with an elimination grid to help you along the way.

Dec 11, 2025 · Puzzles with larger grid sizes and higher difficulty levels will have a larger maximum number of points. To increase the point potential, select a greater grid size or difficulty level (or both).

Who's Online Below you'll find a short list of all registered players currently online, along with their avatar images, last active time, and a link to their personal scorecard. Currently online: 100 registered …

If you're new to grid-based logic puzzles, this tutorial will teach you the basics. Start with the "Introduction" first, then move on to the tutorials discussing specific clues or solving methods.

If you're new to grid-based logic puzzles, this tutorial will teach you the basics. Start with the "Introduction" first, then move on to the tutorials discussing specific clues or solving methods.