What is Straight up?
A straight-up bet in roulette is a wager on a single number, including zero, which pays 35 to 1 if the ball lands on that number.
The chip is placed directly on one number. On a European wheel the probability of winning is 1 in 37. A £5 straight-up bet that wins returns £175 profit plus the £5 stake.
Despite the high payout, the house edge is the same as on most other roulette bets: about 2.70% on a single-zero wheel and 5.26% on a double-zero wheel. The difference between bets lies in volatility, not in expected cost.
Straight-up bets are the smallest of the inside bets. Others, such as splits, streets and corners, cover two, three or four numbers at proportionally lower payouts. Because a single number wins only about once in 37 spins on average, long losing runs are normal for players who favour straight-up bets. Roulette betting systems built around single numbers cannot change these odds.