Custom Minesweeper
Set any width, height and mine count and play it straight away. Custom boards run the same engine as the ranked modes, including the guaranteed-safe first click, so the only thing that changes is the shape of the problem. Custom results are not ranked, because times on different board sizes are not comparable.
What mine density actually does
Board size changes how long a game takes; density changes how hard it is. Density is simply mines divided by cells, and it is the number that decides whether a board is a steady deduction or a minefield of forced guesses. The three classic difficulties sit at very specific points on that scale:
| Preset | Grid | Mines | Density |
|---|---|---|---|
| Beginner | 9 × 9 | 10 | 12.3% |
| Intermediate | 16 × 16 | 40 | 15.6% |
| Expert | 30 × 16 | 99 | 20.6% |
Below roughly 12% a board mostly opens itself and there is little to deduce. Around 15 to 21% you get the classic experience: long chains of solvable logic with the occasional genuine 50/50. Above about 25% the board stops being a puzzle and starts being a lottery, because the numbers constrain each other so tightly that whole regions become unsolvable without a guess. If you want density without the coin flips, play No-Guessing mode, where every board is verified solvable by logic alone before you see it.
Sizes worth trying
Small and fast
A 9 × 9 with 10 mines is the standard sprint. Drop to 7 × 7 with 6 mines and you get a board that resolves in a few seconds, which is the best way to drill a single pattern repeatedly — set one up, play twenty of them, and the 1-2-1 and 1-1 shapes start appearing to you instantly rather than after a pause.
Wide and shallow
A 30 × 8 board has the width of Expert with half the height, so almost every cell is on or near an edge. Edge cells have five neighbors instead of eight, which makes them far more constrained and far easier to solve. It is the friendliest way to practise chording along a wall.
Marathon
At 50 × 50 with 500 mines you get 2,500 cells at 20% density — roughly five Expert boards end to end. These are less about speed than stamina and board reading, and they are where 3BV stops being an abstraction: a board this size can carry a 3BV in the high hundreds, and the difference between an efficient and an inefficient route is measured in thousands of clicks.
Limits
Width and height run from 5 to 50. Mines run from 1 up to whichever is smaller: 85% of the cells, or the cell count minus nine. That second limit exists because the first click is guaranteed safe and opens its eight neighbors, so a board must always keep nine cells free for it.
Where to go next
Ranked play happens on the standard boards: Beginner, Intermediate and Expert, all feeding the global leaderboard. To find out whether a time you just set is any good, run it through Is My Time Good?, and to learn the rules from scratch start with the rules page.