MUN vs ARS·Next Goal — Man Utd2.10MUN vs ARS·Next Goal — No Goal3.40MUN vs ARS·Next Goal — Arsenal2.90RMA vs SEV·Next Goal — Real Madrid1.60RMA vs SEV·Next Goal — No Goal5.00RMA vs SEV·Next Goal — Sevilla3.20INT vs NAP·Next Goal — Inter4.00INT vs NAP·Next Goal — No Goal1.20INT vs NAP·Next Goal — Napoli3.50ALC vs SIN·Match Winner — Alcaraz1.85

Overround

Also called: Bookmaker margin, Vig

Add up the implied probabilities of every outcome in a market. The excess above 100% is the bookmaker's built-in margin.

A perfectly fair market totals 100%; real markets total more, and the excess is the bookmaker's built-in margin. That is why consistently beating the market is hard.

Measuring market margin

Man Utd 2.1047.6%
No Goal 3.4029.4%
Arsenal 2.9034.5%
Total111.5%
Overround11.5%

Note: the same match's Total Cards market (1.85 / 1.95) totals 105.3%, an overround of 5.3% — margins vary by market.

In this demo

The demo's odds are hand-written mock numbers, so their overround is incidental rather than a modelled margin.

Related terms

Implied Probability

The chance of an outcome implied by its price. Divide 1 by the decimal odds and multiply by 100.

Decimal Odds

Decimal odds express the TOTAL return per £1 staked, including the stake itself — not just the profit.

Value Bet

A bet where your own estimate of the outcome's chance is higher than the chance implied by the price.

Arbitrage

When different bookmakers price the same market differently enough that backing every outcome guarantees a profit whatever happens.

Bets.tv is a demo environment showcasing simulated betting limits.

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