The roulette layout looks like it offers a menu of different gambles. It offers one gamble, sliced different ways. Every inside bet — the ones placed on the numbered grid rather than the outside boxes — follows a single formula, and once you see it, the whole table reads as one bet with a coverage dial.

The formula

An inside bet covering n pockets pays 36 ÷ n, minus 1, to one. That is it. The 36 is the number of pockets the table pretends exist; the real wheel has 37, and the missing one is where the house edge lives.

The five inside bets

  • Straight up — one number. Chip in the centre of the box. 36 ÷ 1 − 1 = 35 to 1.
  • Split — two adjacent numbers. Chip on the line between them. 36 ÷ 2 − 1 = 17 to 1.
  • Street — a row of three. Chip on the outer edge of the row. 36 ÷ 3 − 1 = 11 to 1.
  • Corner — four numbers meeting at a point. Chip on the intersection. 36 ÷ 4 − 1 = 8 to 1.
  • Six line — two adjacent rows. Chip on the edge where they meet. 36 ÷ 6 − 1 = 5 to 1.

On our layout you place each of these by tapping the position: the centre of a number, the line between two, the row edge, the intersection, or the meeting point of two rows. The chip's position on the felt is the bet.

Why coverage does not help

A corner wins four times as often as a straight-up bet and pays a little under a quarter as much. Run it out over 37 spins at one chip: the corner wins 4 times, collecting 8 chips each plus the stake, 36 chips back for 37 out. The straight-up bet wins once, collecting 35 plus the stake, 36 back for 37 out. Identical. Every inside bet returns 36 chips per 37 wagered in the long run. Coverage changes how often you win and how much; it never changes how much you keep.

What it does change

Variance. A straight-up bet is a long wait for a big return; a six line is a steady trickle of small ones. Neither is better. If you enjoy the drama of a single number hitting, play numbers and expect long dry spells. If you would rather see chips come back regularly and go home with something close to where you started, spread across corners and lines. The house edge on both is the 2.70% in single zero versus double zero; the experience is entirely different.

The one inside bet to notice

On a double-zero wheel there is a five-number bet covering 0, 00, 1, 2 and 3 that pays 6 to 1. Apply the formula: 36 ÷ 5 − 1 is 6.2, and the table rounds down. That rounding makes it the only inside bet with a worse edge than the rest — 7.9% instead of 5.26%. It does not exist on a single-zero wheel, which is one more small reason to prefer one. Everything else on the grid is the same bet, and as the ball's bounce makes sure, none of it can be aimed.