Expert Mini Sudoku (4×4)

A compact 4×4 grid using digits 1–4. Each row, column, and 2×2 box must contain every digit once. Quick to solve, satisfying to master. Free online.

Easy Medium Hard Expert

Expert Mini Sudoku. The hardest 4×4 puzzles on the site — almost no given digits, requiring precise logical deduction across all 16 cells.

2
1
4
3
2
Mistakes
0/3
Score
-
Time
00:00
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Progress0%

What is Mini Sudoku?

Difficulty
★☆☆☆☆
1/5
Constraint Type
Smaller Grid
Typical Givens
4–8
Avg. Solve (Expert)
6 min

Solving Techniques for Expert Level

Technique Description Level
Direct Scanning With only 16 cells and digits 1–4, scan each row, column, and 2×2 box for missing digits. Most easy puzzles resolve in a single pass. Beginner
Single Candidate If only one cell in a row, column, or box can hold a particular digit, place it immediately. Beginner
Box–Row/Column Interaction Each 2×2 box shares all four cells with exactly two rows and two columns. Every box placement simultaneously restricts two full rows and two full columns. Beginner

Average Solve Time by Difficulty

Easy
1 min
Medium
2 min
Hard
4 min
Expert
6 min
Want a full walkthrough of rules, strategies, and solving steps? How to Play Mini Sudoku →

Frequently Asked Questions — Expert Mini Sudoku

Is expert Mini Sudoku harder than standard easy Sudoku?
Expert Mini Sudoku rivals easy standard 9×9 Sudoku in the reasoning depth required. The 4×4 grid has very few cells, so expert puzzles are crafted to have almost no obvious placements. Every deduction requires combining all three constraint types — row, column, and 2×2 box — simultaneously.
What is the hardest technique needed for expert Mini Sudoku?
The hardest technique in a 4×4 grid is a forcing chain: assume digit X in cell A, follow the forced placements through the rest of the grid, and check whether a contradiction arises. Because the grid is tiny, chains are short — usually just three or four steps — but they must be executed precisely.
How many givens does an expert Mini Sudoku have?
Expert 4×4 Mini Sudoku puzzles typically have only three to five pre-filled cells — the minimum required for a unique solution. All other 11–13 cells must be determined entirely by logical deduction from those sparse clues.
How do I set up for an expert Mini Sudoku?
Fill in the candidates (from 1–4) for every empty cell immediately. With so few givens, many cells will start with three or even four candidates. Then apply every available elimination — rows, columns, 2×2 boxes — to reduce those candidates. Expert puzzles usually have exactly one pivotal cell whose value can be forced; finding it is the challenge.
How long does an expert Mini Sudoku take?
Expert Mini Sudoku takes most players 10–20 minutes despite the small grid. The puzzle is short but dense — every move matters and mistakes cascade quickly across only 16 cells. Take it methodically: list all candidates, eliminate systematically, and you will reach the solution without guessing.

More questions? See the full Mini Sudoku guide.