Odds, Probability & Bankroll
Negative betting odds explained
Negative betting odds are American moneyline prices below zero that tell you how much you need to risk to make a 100-unit profit, marking the outcome as the favourite.
Key points
- Negative odds indicate the favourite; the larger the absolute value, the more heavily favoured the outcome.13
- −400 corresponds to fractional odds of 1/4, showing the same implied probability in a different format.12
- The implied probability for negative odds is calculated as |X| / (|X| + 100).13
Where this term is used
Not the same as
- Sports betting odds explained — a broader term covering all odds formats, whereas negative odds are only the American/moneyline subtype
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Sources
- Odds en.wikipedia.org Defines negative moneyline odds and the stake-to-profit convention.
- Fixed-odds betting en.wikipedia.org Provides the fractional equivalent example (−400 = 1/4) and confirms the format.
- Player Props: Understanding the Math Behind the Lines wizardofodds.com Gives the −150 example and the implied probability formula.
Sources are drawn from regulators, universities and published research, and each one is labelled with what it actually is — a preprint is not called a paper. Bookmaker and affiliate pages are never cited here, because a page that sells betting is not a neutral authority on it.