Single-spin probability
A bet covering k distinct pockets on a wheel with N pockets wins with probability k/N. It loses with probability (N−k)/N.
Coverage must not double-count overlapping chips when evaluating a portfolio of wagers.
Expected value
For a one-unit bet with net win payout P, player EV is (k/N × P) − ((N−k)/N × 1). The negative of player EV is the expected casino win per unit.
A single-zero straight-up bet gives (1/37 × 35) − (36/37) = −1/37.
Repeated spins
If spins are independent, the chance an event misses n times is (1−p)^n. The chance it appears at least once is 1−(1−p)^n.
These formulas describe a planned sequence before it occurs. A long completed miss does not make the next spin more likely.
Multiple bets
Add the expected value of each chip to obtain portfolio expectation. Overlapping outcomes affect variance and settlement, but they do not cancel the edge.
The site calculator can model coverage and payout without implying that a likely win is a profitable bet.
Practical checklist
- Use total wheel pockets
- Count unique covered outcomes
- Enter net payout
- Separate probability from expected value
- Do not apply sequence probability to a single next spin
Rules, probabilities, and payouts apply only to the model stated on this page. Posted casino rules control when they differ. Last reviewed September 20, 2026.