Roulette reference

Roulette Glossary

A focused glossary of roulette terms used across the simulator, calculators, bet pages, and strategy guides.

Quick answer

Start with house edge, payout, inside bet, outside bet, bankroll, and expected value. Those terms explain most roulette guides and calculators on this site.

Roulette terms

American roulette: A roulette wheel with 0, 00, and 1-36. The extra double zero raises the house edge on standard bets. Learn more
Bankroll: The amount of money or practice balance set aside for a roulette session. Learn more
Column bet: A bet on one vertical column of 12 numbers with a 2:1 payout. Learn more
Corner bet: An inside bet covering four adjacent numbers with an 8:1 payout. Learn more
Dozen bet: An outside bet covering 1-12, 13-24, or 25-36 with a 2:1 payout. Learn more
European roulette: A roulette wheel with one zero and numbers 1-36. It is the lower-house-edge baseline used by this site. Learn more
Expected value: The long-run average result of a bet after accounting for probability and payout. Learn more
House edge: The average mathematical advantage built into roulette payouts. It is 2.70% on European standard bets and 5.26% on American standard bets. Learn more
Inside bet: A bet placed on the numbered grid or between numbers, usually covering fewer numbers with a larger payout. Learn more
Line bet: An inside bet covering six numbers across two adjacent rows with a 5:1 payout. Learn more
Outside bet: A bet placed outside the numbered grid, usually covering 12 or 18 numbers with lower payouts and lower variance. Learn more
Payout: The profit paid on a winning bet before the original stake is returned. A 35:1 payout earns 35 units of profit for each unit staked. Learn more
Progression system: A betting pattern that changes stake size after wins or losses. It changes variance, not the house edge. Learn more
Split bet: An inside bet covering two adjacent numbers with a 17:1 payout. Learn more
Straight up bet: An inside bet on one exact number with a 35:1 payout. Learn more
Street bet: An inside bet covering a horizontal row of three numbers with an 11:1 payout. Learn more
Unit size: The base amount used for each flat bet or each step in a betting system. Learn more
Zero: The green pocket that creates the house edge because most outside bets lose when zero hits. Learn more