Each bingo player is given a card marked with a grid containing a unique combination of numbers. The winning pattern to be formed on the card is announced. On each turn, a non-player known as the caller randomly selects a numbered ball from a container and announces the number to all the players. The ball is then set aside so that it cannot be chosen again. Each player searches his card for the called number, and if he finds it, marks it. The element of skill in the game is the ability to search one's card for the called number in the short time before the next number is called.

The caller continues to select and announce numbers until the first player forms the agreed pattern (one line, two lines, full house) on their card and shouts out the name of the pattern or bingo. One of the most common patterns, called full card, blackout and cover-all simply consists of marking all the numbers on the card. Other common patterns are single line, two lines, the four corners, centre cross, L, T, Y, postage stamp (2x2 and in a corner) inner square (4 ? 4), roving square (3 ? 3), and roving kite (a 3 ? 3 diamond). Lines can be made horizontally, vertically, or diagonally. Inner and roving squares and kites must be completely filled; roving squares and kites may be made anywhere on the card.

Bingo cards are flat pieces of cardboard or non-reusable paper which contain 25 squares arranged in five vertical and five horizontal rows; Dual dab, or "double-action" cards have two numbers in each square. Each space in the grid contains a number, except for the center square, which is considered filled. The highest number used is 75. The letters B, I, N, G, O are pre-printed above the five vertical columns, with one letter appearing above each column. The center space is marked "free." The printed numbers on the card correspond to the following arrangement: 1 to 15 in the B column; 16 to 30 in the I column; 31 to 45 in the N column; 46 to 60 in the G column and 61 to 75 in the O column.

There are 552,446,474,061,128,648,601,600,000 (five hundred fifty-two septillion, four hundred forty-six sextillion, four hundred seventy-four quintillion, sixty-one quadrillion, one hundred twenty-eight trillion, six hundred forty-eight billion, six hundred one million, six hundred thousand) possible arrangements of the numbers on a bingo card.