Roulette Odds Calculator

Why every bet has the same edge

This surprises people the first time they see it. On a European wheel, a straight-up bet on 17 and a bet on red have identical expected value: you lose 2.70% of whatever you stake. The payout structure is tuned so that the missing unit is proportionally the same everywhere.

Change the wheel and everything shifts at once. Add the double zero and every bet moves to 5.26%. Add La Partage and the even-money bets — and only those — drop to 1.35%. That is the entire decision tree for choosing a roulette table.

Reading the expected value line

Expected value is the average result per spin across an enormous number of spins. It is not what will happen tonight. A $10 even-money bet has an expected value of -$0.27, but the actual outcome of any single spin is +$10 or -$10 — never -$0.27.

Its usefulness is in planning: multiply by the number of spins you expect to play, and you have a budget figure that is far more reliable than intuition.

A worked example

Set the wheel to European and the bet to a corner (four numbers). The calculator returns a 10.81% chance, true odds of 8.25 to 1, a payout of 8 to 1 and an edge of 2.70%.

The quarter-unit gap between 8.25 and 8 is the entire business model. Across 37 spins staking $10 on a corner you wager $370, win four times, and collect $360. The $10 difference is 2.70% of turnover — the same figure the straight-up bet produces, and the same figure red produces.

How to use it before a session

1. Pick the wheel you will actually be playing. This is the only input that changes the answer materially.
2. Enter your real stake, not a round number.
3. Read the bottom line — expected cost over 100 spins. Multiply by however many hundreds of spins your session will run.
4. If that figure is uncomfortable, change the wheel or the stake. No other adjustment helps.

Privacy and how this tool runs

Everything on this page is computed in your browser. Nothing you type is transmitted, logged or stored anywhere, there is no account, and the page works offline once loaded. The source is plain JavaScript in the page itself — you are welcome to read it.

All our figures use published paytables and pocket counts. If you find a number here you believe is wrong, tell us: we correct in place and change the date at the top of the page.