How to Play Minesweeper

Minesweeper is a single-player logic puzzle. The goal is simple: reveal every safe square on the board without clicking a mine. No guessing is needed in most situations — the numbers tell you everything.

What is Minesweeper?

Minesweeper is one of the most recognizable puzzle games ever made. Originally bundled with Microsoft Windows in 1990, it challenges players to clear a rectangular grid of hidden squares without detonating any mines. The game rewards careful logic over speed, though experienced players often chase personal best times once they master the fundamentals.

The objective

You win by revealing every square that does not contain a mine. You lose the instant you click on a mine. Flags are a bookkeeping tool — placing them is optional but strongly recommended, because they help you visualize which squares are accounted for.

Step-by-step rules

  1. Click any square to start. Your first click is always safe — mines are placed after you click, so you are guaranteed an open area to begin reasoning from.
  2. Read the numbers. Each revealed number tells you exactly how many mines are hidden in the eight squares surrounding it (horizontally, vertically, and diagonally).
  3. Flag suspected mines. Right-click (or press F on keyboard) to place a flag on a square you believe contains a mine. Flags help you keep track of dangerous squares so you can safely reveal the rest.
  4. Use logic to clear the board. Compare neighboring numbers to work out which squares must be safe and which must be mines. If a number already touches enough flags, every other neighbor is safe to reveal.
  5. Win by revealing every safe square. You win when every non-mine square has been revealed. You do not need to flag every mine — revealing all safe squares is enough.

Understanding the numbers

The number on a revealed square tells you how many of its eight neighbors (up, down, left, right, and the four diagonals) contain mines. A 1 means exactly one neighbor is a mine. A 3 means three of the eight surrounding squares are mines. A blank (zero) means no neighbors are mines — and the game automatically reveals all adjacent blanks in a cascade, giving you a large safe area to work from.

Corner squares have only three neighbors, and edge squares have five. Keep this in mind — a 2 on a corner is far more constraining than a 2 in the middle of the board.

Flagging mines

When you are confident a square contains a mine, right-click it (or press F on your keyboard) to place a flag. Flagged squares cannot be accidentally clicked. The mine counter at the top of the board decreases as you place flags, helping you track how many mines remain unaccounted for.

First-click safety

On online-minesweeper.io your very first click is always safe. Mines are placed after you click, and the clicked square plus its neighbors are excluded from mine placement. This guarantees you begin every game with an open area to reason from, rather than hitting a mine on the first move.

Keyboard controls

You can play the entire game without a mouse. Use arrow keys to move between cells, Space or Enter to reveal a cell, and F to toggle a flag. Home, End, Page Up, and Page Down jump to the edges of the board.

Difficulty levels

Three classic board sizes are available, plus a custom option and a daily challenge:

  • Beginner — 9 × 9 board, 10 mines. Ideal for learning the basics.
  • Intermediate — 16 × 16 board, 40 mines. A good balance of speed and deduction.
  • Expert — 16 × 30 board, 99 mines. The full challenge — pattern recognition, edge logic, and careful bookkeeping.

Ready for more? Read the strategy guide or check out quick tips for beginners.