Understanding Odds

Learn to read decimal odds, calculate your returns and understand the bookmaker margin.

What is an odd?

An odd is a number that represents the multiplier applied to your stake if you win. Odds of 2.00 means you double your stake. Odds of 1.50 returns 1.5× your stake. The higher the odds, the less likely the bookmaker thinks the outcome is.

Decimal odds

In Europe, odds are expressed in decimal format. Example: odds of 2.50 on a £10 stake = £25 gross return (£15 net profit). The formula is simple: Return = Stake × Odds.

The bookmaker margin

Every bookmaker builds a margin into their odds (called "overround" or "vig"). If the true probability of an event is 50%, the bookmaker will offer odds of 1.90 instead of 2.00 — that's their ~5% margin. Over the long run, this is what guarantees them a profit.

Implied probability

To convert odds to probability: Probability = 1 / Odds × 100. Odds of 2.00 = 50% implied probability. Odds of 1.50 = 66.7%. The lower the odds, the more likely the bookmaker considers the outcome to be.

How to compare odds?

Always compare odds across multiple bookmakers before placing a bet. A difference of 0.10 may seem small, but over hundreds of bets it represents tens of percentage points of additional ROI. Use our odds comparator to find the best odds in real time.