The odds of hitting a single number in roulette, also known as a Straight Up bet, are 35:1. This means that for every 1 unit you bet, you'll win 35 if your chosen number comes up. Keep in mind, the actual probability of winning a Straight Up bet is 2.7% on a European wheel (1 in 37) and 2.6% on an American wheel (1 in 38), due to the extra double zero on the American roulette wheel.