Build an exact Minesweeper puzzle

The creator is for authored mine layouts: teaching examples, shaped boards, club challenges and positions that must remain exactly the same. Click any cell to add or remove a mine. Every safe cell immediately displays the number of mines in its neighboring cells, so you can inspect the clue field while designing.

Set the column and row counts, then choose Resize before placing mines.
Click cells to create the intended mine pattern, or use Random layout as a starting point.
Review the mine count, density and clue numbers. Use Clear when you want an empty design.
Choose Test puzzle and play from several openings.
When the behavior is correct, choose Copy playable link and share the exact challenge.

Choose useful dimensions and density

Small boards make focused logic lessons easier to read. Larger boards are better for complete games but take longer to inspect. The creator supports 5 to 30 columns and 5 to 24 rows. Resizing downward discards mine positions that fall outside the new dimensions, so choose the final size before doing detailed work.

Density is the mine count divided by total cells. Classic presets sit in a relatively narrow range: Beginner is about 12.3%, Intermediate about 15.6%, and Expert about 20.6%. Those values are useful reference points, not design rules. A teaching puzzle may be much sparser, while a decorative mine shape may be denser but less pleasant to solve.

How clue numbers are calculated

Each safe cell counts mines in up to eight surrounding positions: above, below, left, right and the four diagonals. Corner cells have three possible neighbors and ordinary edge cells have five. The displayed number updates after every mine edit. A blank safe cell means zero adjacent mines and would normally open a larger area through flood fill during play.

Test solvability before sharing

The creator validates dimensions and produces consistent clue numbers, but it does not certify that the puzzle has a unique solution or a deduction-only path. An exact layout can still contain a forced guess, an unhelpful first move, multiple equivalent solutions or an opening that exposes most of the board immediately.

Try the puzzle from the opening you expect recipients to use.
Check whether every intended deduction uses only information already visible at that point.
Enter important frontiers in the Minesweeper solver to see whether cells are genuinely forced.
Ask another person to solve without seeing the mine layout.
Verify the copied link in a private window before publishing it widely.

What the share link contains

The URL encodes the width, height and exact mine indices. The receiving browser opens the layout in the local player; it does not create a public database record, upload an image or add the puzzle to a searchable directory. Anyone with the link can reproduce and decode the mine map, so it is suitable for open challenges and lessons rather than secret competitions.

Custom-layout games are unranked. Standard rankings rely on server-created sessions and validation rules that authored URLs do not have. If you want a reproducible random board instead of a fixed mine map, use a seeded challenge from Offline Minesweeper.

Puzzle creator questions

Can I make a no-guess puzzle?

Yes, but the creator does not prove that property automatically. Design the layout, choose the intended opening, and verify each step with logical play or the solver. A no-guess claim should describe the opening because a different first click can expose a different problem.

Why did some mines disappear after resizing?

Mines are stored as cell indices inside the current grid. When the board becomes smaller, positions outside the new bounds cannot be retained and are removed.

Can I edit a shared puzzle later?

The link is a snapshot of its encoded layout. Return to the creator, make a revised layout and copy a new URL. Existing links continue to represent the old version.

Are puzzle links permanent?

The layout data is in the URL, so it does not depend on a saved database row. It will remain reproducible while the compatible local player exists, but you should still archive important designs in your own notes.