Slitherlink Solver
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Slitherlink Solver — Step by Step

Click a square and type its number (0–3). Leave blank squares empty. Then press Solve. Or play a generated puzzle and send it here with one click.

Slitherlink Solver: rules, how to use it, tips

Join the dots into one closed loop so that each number says how many of its square’s four sides the loop uses.

The rules

  1. Draw lines between neighbouring dots, across or down — never diagonally.
  2. The lines must form one single closed loop.
  3. The loop cannot cross itself or branch: every dot has no lines or exactly two.
  4. A number tells how many sides of its square are part of the loop. Blank squares can have any number.

Using the solver

  1. Choose the size, click each numbered square and type its number (or press Sample).
  2. Press Solve and step through: zeros, full numbers, following the line from dot to dot, and why small loops are impossible.

Tips

The full guide, with a worked example and common mistakes: How to play Slitherlink.

Questions

Can the loop touch itself at a corner?

No — each dot has at most two lines, so the loop never touches or crosses itself.

Do I have to use every dot?

No. Many dots stay unused; only the numbers have to be satisfied.

Is there always one answer?

Yes — every puzzle here is checked to have exactly one loop.

How do I solve one from a newspaper?

Open the Slitherlink Solver, type the numbers and press Solve.

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