Roulette odds calculator
Pick a bet and a wheel. See its chance on one spin, its posted payout, and what a flat-stake session can return. Every figure comes from the pockets and payout rules, with no sampled runs.
Where the session can finish
These are probabilities across repeat sessions. They do not predict this one. A win pays 1:1; a miss loses the stake.
Read the result
This bet covers 18 of 37 pockets, so its single-spin win chance is 18/37. At $10 per spin,100 spins put $1,000 on the table. The expected loss is $1,000 × (1/37), about $27.03. At least one hit occurs in more than 99.99% of such sessions. The chance of no hit is exactly (19/37)100, so a hit is never certain. A hit alone does not guarantee a profit.
The session calculation counts the possible numbers of winning spins. After w wins, the net is stake × [w × (1 + 1) − 100]. It adds the exact binomial probabilities for outcomes above, at and below zero. It assumes the same bet and stake on independent spins of a fair wheel. It does not model table limits, bankroll stops, bet progressions, or French zero concessions.
Go deeper
See the red / black, odd / even, 1–18 / 19–36 guide for placement, droughts and worked odds. Compare every bet on the odds index, check the wheel rules, or run the simulator with a reproducible seed. The simulator currently supports standard European and American settlement only.