Sudoku-Y
SUDOKU · 1–9

4×4 Sudoku

Sixteen cells to practise the essentials.

Stuck, or just getting started? Let’s practise ↓

No repeats in any row, column or box

Mistakes 0
00:00
Preparing your gameMedium

Use 1–9 to enter numbers
and arrow keys to select a cell

PLAY · NOTICE · TRY

One small move at a time.

Pick a step below. You can try, get it wrong and start again. Your saved game stays here.

  1. Start with one cellCheck a row, a column and a box.
  2. Spot the only choiceTry a Single before peeking at the answer.
  3. Let a pair help youTwo cells, two digits. What can go?
  4. Connect a box and a rowTry both directions, then change a condition.
Try 12 practice topics →Browse all techniques →Which board size should I try? →
A fresh perspective

Start with the row, column or box that has the most numbers
Fewer empty cells can make the next answer easier to spot

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4×4 Sudoku — rules and practice

Fill each row, column and 2×2 box with the digits 1–4, without repetition. The core rules match Classic 9×9, but there are fewer cells to inspect. This makes the small grid useful when explaining why a particular number belongs in a cell.

Recognise the four boxes

Thicker lines divide the board into four boxes containing four cells each. A placement must respect its box as well as its row and column. A digit missing from a row may already be present in the target box, so checking only the row is not enough.

Practise without filling every pencil note

If one unit already contains 1, 2 and 4, its remaining cell must be 3. Become comfortable with this deduction before recording many candidates. Use Notes when more than one option remains. Undo lets you revisit an entry without discarding the whole puzzle.

Choose your next step

Once you can explain your placements, try 6×6 for a larger candidate set or Classic 9×9 for the advanced technique scanner. A smaller board does not mean every puzzle has the same difficulty: the starting digits and deductions still matter.

Try a small example

Original four-cell row example: which number is missing?

2?13
Show reasoning

4. The row needs 1, 2, 3 and 4 once each. This teaching example shows one row condition, not a full puzzle.

Common questions

Can I use zero?

No. A 4×4 game uses the digits 1–4. Leave an undecided cell empty.

Can I resume later?

Yes. Classic 4×4 has its own saved session in this browser, separate from other sizes. It resumes while that local data remains available.

Learn on your next puzzle

Original examples and explanations by Sudoku-Y. Editorial process and sources ·