Sudoku 4×4
A simplified 4×4 Sudoku for beginners learning the rules. Gentle introduction to constraint logic. Fill the grid so every row, every column, and every 2×2 box contains the digits 1-4 exactly once each.
How to play 4×4 Sudoku
4×4 Sudoku is the beginner-friendly version of the classic 9×9 puzzle. The grid has 4 rows, 4 columns, and 4 boxes of 2×2 cells each. Your goal is to fill every empty cell with a digit from 1 to 4 so that no digit repeats in any row, any column, or any 2×2 box. Some cells are pre-filled ("given"); these are the clues that make the solution unique.
The smaller grid is perfect for learning the rules without the cognitive load of the full 9×9 version. Once you can comfortably solve a 4×4 in under two minutes, you're ready to move up to Sudoku 9×9. For detailed solving techniques that work on both sizes — naked singles, hidden singles, scanning — see our Sudoku solving techniques guide.
Worked example
Suppose you have a row that already contains 2, 4, and
1. The only remaining digit for the empty cell is 3, because
each row must contain every digit from 1 to 4 exactly once. This is the simplest
solving technique, called a naked single: a cell whose row, column,
and box together leave only one possible candidate.
Why this size exists
The 4×4 version is widely used to teach Sudoku to children and to adults who find the 9×9 grid intimidating. The math is gentler (only 4 candidates per cell instead of 9), the boxes are 2×2 instead of 3×3, and a typical puzzle solves in 1-3 minutes. The underlying logic is identical to the larger version — every concept you learn here (elimination, hidden singles, box-and-row interactions) carries over directly.
Difficulty
The puzzles on this page are generated with a moderate number of givens (typically 6-8 of 16 cells filled in). They are designed to be solvable through straightforward elimination without requiring advanced techniques. If you want a harder challenge, the 9×9 version offers multiple difficulty levels.
How the puzzle is generated
Each puzzle is generated client-side by JavaScript: the script fills a 4×4 grid with a valid full solution, then removes cells at random until a target number of givens remains. Because the underlying solution is always valid, every puzzle has exactly one solution (we verify this by checking that each cell's value is forced by the remaining clues before we ship the puzzle to you).