Football Betting Odds: Meaning, Probability, and Return

Three formats can describe the same price

The examples are equivalent before rounding. DraftKings' betting terminology is one current operator glossary; displayed conventions and rounding can vary by product.

Decimal odds calculations

For positive decimal price d:

• raw implied probability = 1 / d;
• possible gross return = stake * d;
• possible profit = stake * (d - 1).

At decimal odds of 1.80 with a GBP 20 stake:

• raw implied probability = 1 / 1.80 = 0.5556, or 55.56%;
• possible gross return = GBP 20 * 1.80 = GBP 36.00;
• possible profit = GBP 36.00 - GBP 20 = GBP 16.00;
• maximum loss for the fixed-odds single = GBP 20.

The 55.56% figure is a price conversion before removing margin. It is not a guarantee and does not establish a true probability. OpenStax describes probability as uncertainty over outcomes.

Fractional and American conversions

For positive fractional odds a/b:

• decimal odds = 1 + a / b.

Therefore 3/2 becomes 1 + 3 / 2 = 2.50.

For positive American odds A:

• decimal odds = 1 + A / 100.

Therefore +150 becomes 1 + 150 / 100 = 2.50.

For negative American odds -A, using the positive magnitude A:

• decimal odds = 1 + 100 / A.

Therefore -200 becomes 1 + 100 / 200 = 1.50.

Price without a contract is incomplete

Odds of 2.50 do not identify the event, market, qualifying period, team or player scope, void conditions, or accepted stake. A standard match-result price can settle at regulation time while a to-qualify price can follow extra time and penalties. Betfair's general sportsbook rules are one operator example of fixed-odds and settlement conditions; the actual accepted market rule controls.

Displayed and accepted prices can differ

A displayed price is not necessarily the final contract. Betfair's general sportsbook rules are one operator example in which acceptance and confirmation determine whether a bet exists. A price can move before acceptance, while price-change settings can determine whether an instruction is rejected or proceeds at another price. Record the market and price shown, the submitted instruction, the accepted price and timestamp, and the possible return on the final receipt. Calculate from that accepted record rather than an earlier screen.

Margin and probability estimates are deeper tasks

If mutually exclusive market prices convert to more than 100%, the excess is a simple overround measure. Removing margin requires a declared method, and no mechanical method proves the true probabilities. Expected value also requires an independently estimated outcome distribution; OpenStax expected value concerns long-run averages across outcomes.

Use the Betting Odds Explained pillar for margin removal, probability, price comparison, exchange prices, and model-price evaluation. This page owns the beginner orientation rather than repeating those methods.

Continue learning

• Next guide: Football Betting Rules
• Related guide: How Bookmakers Make Money

Assumptions and limitations

Examples use positive prices and ignore commission, tax, promotions, partial matching, pushes, and currency conversion. Operators can round displays differently. The accepted price, market rule, stake or liability, and receipt determine the actual contract.