Mines simulator and calculator

How the mines calculator works

A board has 25 tiles and m mines. The chance that your first k picks are all safe is C(25 − m, k) / C(25, k), where C is the number of combinations. A fair game would pay the inverse of that chance. Crypto casinos take a 1% edge, so the multiplier after k safe picks is 0.99 × C(25, k) / C(25 − m, k).

With 3 mines the first safe tile is a 22 in 25 shot (88%) and pays 1.125×. Two safe picks pay 1.29×, five pay 2.00× and ten pay 5.00×. With 24 mines a single safe tile pays 24.75× because you had a 1 in 25 chance of finding the only gem.

Every stopping point has the same RTP

Multiply the win chance by the multiplier and the combinations cancel out, leaving 0.99. That holds for any mine count and any number of picks, so the return to player is 99% whether you take one tile with one mine or chase the last gem with 24 mines. The table under the board lists every multiplier and win chance for the mine count you choose.

What changes is variance. Few mines and few picks win most rounds for small profits. Many mines or many picks lose most rounds and occasionally pay hundreds or thousands of times the bet.

Testing a Stake mines strategy

Common Stake mines strategy advice says to use 3 mines and cash out after 2 or 3 tiles, or to pick corners first. Tile choice makes no difference: mines are placed at random before you click, so every hidden tile has the same chance of being a mine. Cashing out early only trades a higher win rate for a smaller payout.

Use the Auto ×1,000 button to check. Set a mine count and a number of picks, run a batch and compare the observed win rate and RTP with the expected values. Over a few thousand rounds the RTP settles near 99% for every setting.

• Win chance for k picks = C(25 − m, k) / C(25, k).
• Next-tile safe chance = (25 − m − k) / (25 − k) after k safe picks.
• Expected loss per round = bet × 1% regardless of settings.