Build Your Own Custom Minesweeper Board
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
Mine density is the number of mines divided by the number of cells. Higher density generally puts more mines around each clue, but density alone does not decide difficulty. The exact layout, board shape, opening size and whether a position forces a guess also matter. The three classic settings provide useful reference points:
| Preset | Grid | Mines | Density |
|---|---|---|---|
| Beginner | 9 × 9 | 10 | 12.3% |
| Intermediate | 16 × 16 | 40 | 15.6% |
| Expert | 30 × 16 | 99 | 20.6% |
Beginner, Intermediate and Expert increase from 12.3% to 20.6%, but two boards at the same density can still play very differently because their mines create different openings and clue chains. Use density to describe a board, not as a guaranteed difficulty score. If you want custom-like variety without forced guesses, 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 shorter board for repeating basic deductions. Play several with the same settings to practise recognizing 1-2-1 and 1-1 shapes under consistent conditions.
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, so their clues constrain fewer possible cells than clues in the middle. It is a useful shape for practising chording along a wall.
Marathon
At 50 × 50 with 500 mines you get 2,500 cells at 20% density, compared with 480 cells on the classic Expert board. Use the 3BV calculator to measure the exact layout you generated instead of estimating its workload from size or density alone.
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.
Custom Minesweeper FAQ
What is the largest Minesweeper board you can play?
On Minesweeper.now a custom board can be up to 50 by 50 cells, which is 2,500 cells - roughly five Expert boards. Mines are capped at 85% of the cells, and always leave nine cells free so the guaranteed-safe first click has somewhere to open.
What is a good mine density for a custom board?
Between 15% and 21% gives the classic Minesweeper experience. Beginner is 12.3%, Intermediate 15.6% and Expert 20.6%. Below 12% boards largely open themselves; above about 25% they force guesses that no amount of logic can resolve.
Do custom Minesweeper games count on the leaderboard?
No. Times on different board sizes are not comparable, so custom results are not ranked. Ranked play uses the three standard boards: Beginner, Intermediate and Expert.