01
Sudoku
Classic logic. Refined interface.
Category
Free Logic Puzzles
A good logic puzzle has exactly one solution and never requires a guess. Everything you need is on the board — the only question is which constraint to read first. These are the deduction games on Puzzle Theory, all free and all solvable by reasoning alone.
Logic puzzles you can play right now
Constraint puzzles and grouping puzzles
Constraint puzzles such as Sudoku and Domino Regions give you rules that every cell must satisfy simultaneously, and you solve them by finding the cell where the fewest options remain. Grouping puzzles such as Categories give you a flat set of items and ask you to partition it, which is a different skill: you are testing hypotheses, not eliminating candidates.
Solving without guessing
When a logic puzzle stalls, the usual cause is scanning at the wrong scale. Switch from looking at a cell to looking at a unit — a row, a column, a region — and ask where a given value can still go. Almost every apparent dead end in Sudoku resolves the moment you change from 'what fits here?' to 'where can this go?'.
Logic puzzles — frequently asked questions
Are these logic puzzles free?
Yes. Every daily logic puzzle is free with no account required.
Do the puzzles always have a unique solution?
Yes. Sudoku grids and Domino Regions boards are generated and then verified by a solver, so every published puzzle has exactly one solution and can be reached by deduction alone.
Can I choose the difficulty?
Sudoku offers several difficulty levels, and Categories has an expert 5x5 mode. The daily puzzle in each game is the same for every player.
What is Domino Regions?
A placement puzzle where you fill coloured regions with dominoes so that every sum, equality and comparison constraint on the board is satisfied at once. It is closest in spirit to constraint puzzles like Pips.
Is Categories a logic puzzle or a word puzzle?
Both — the items are words but the work is partitioning under uncertainty, so it appears in each category.
Further reading
Guide
Free Online Logic Puzzles: The Best Games to Stretch Your Brain
A practical guide to the best free online logic puzzles — from Sudoku and category-sorting to domino placement — and how to pick the right one for the way you think.
Read GuideLogic Puzzles With Numbers and Shapes: A Beginner's Guide
A gentle introduction to logic puzzles that combine numbers and shapes — including Sudoku, Domino Regions, and region-based grids.
Read GuideNYT Games Sudoku: Difficulty Tiers and Free vs Paid
How does NYT Games Sudoku work? Easy, Medium, and Hard tiers explained, plus what's free vs paid. Try a free daily Sudoku board →
Read