Roulette
Single-number roulette odds
Every individual pocket on a fair wheel has the same chance. A straight-up bet pays 35:1 under standard rules, including a bet on zero.
2.70%
One chosen number, European wheel
1 / 37 • Standard payout 35:1
One number out of the whole wheel
A chosen number wins with probability 1/37 on European roulette, 1/38 on American roulette and 1/39 on triple zero. These are about 2.70%, 2.63% and 2.56% respectively. No number has a built-in advantage.
True odds and payout odds differ
With 37 pockets there are 36 losing outcomes for one winning outcome. True odds against are 36:1, while standard net payout is 35:1. That gap produces the house edge.
The same number twice
Before two spins, the chance of a particular number appearing both times is (1/37)^2 on a European wheel. If the first result is already known and any matching second result counts, the chance of a repeat on the next spin is 1/37.
Number labels and colors
A query mentioning 11, 17, 22 or 32 still describes one pocket if a straight-up bet is meant. Choosing a number because it appeared often in a short history does not alter its next-spin probability on a fair wheel.