Why an even-money payout does not mean a 50% chance
Even money describes the payout ratio. It does not, by itself, describe the probability of winning.
The distinction that matters
In a model with 18 red pockets, 18 black pockets and one zero, a red bet has winning probability 18/37. If red pays one unit profit and all other outcomes lose one unit, expectation is 18/37 − 19/37 = −1/37. The zero makes the winning probability lower than one half.
A worked example
With a C$10 illustrative stake, a red result returns C$20 including the stake, while a losing result returns zero. Neither the C$20 gross return nor the phrase 'even money' removes the extra losing outcome from the probability calculation.
Your next steps
- Separate payout odds from outcome probability.
- Count all outcomes that cause the bet to lose.
- Check whether a special zero rule changes the loss.
- Use net amounts consistently in the expectation formula.
Where this answer stops
These assumptions do not cover every roulette variant. A displayed payout must be read together with the settlement rules. The calculation offers no prediction of the next colour.
Sources & reading
Primary references support the factual context below. Explanations, worked examples and calculations are original Northline analysis. Read how we handle evidence.
- OLG PlaySmart — European roulette
Background comparison of wheel variants. Northline articles independently derive stated mathematical models and do not infer table availability. Accessed .
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