How Betting Odds Work

Betting odds are the foundation of sports betting, determining the potential payout of a bet. Whether you're a casual punter or a matched bettor, understanding how odds work is essential for making informed decisions. In this guide, we'll break down the different types of odds, how they are calculated, and why decimal odds are the preferred choice for matched betting.

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Types of Betting Odds

Bookmakers display odds in various formats, but the most common ones in the UK and worldwide include:

• Decimal Odds (European Format)
• Fractional Odds (UK Format)
• American Odds (Moneyline)

Decimal Odds (Recommended for Matched Betting)

Decimal odds are the simplest to understand and the preferred format for matched betting. The total payout (including the stake) is calculated by multiplying the stake by the decimal odds.

For example:

• A bet at 3.00 with a stake of £10 returns £30 (including the £10 stake).

Most UK bookmakers allow users to convert odds to decimal format, and it is highly recommended to do so for ease of calculation when matched betting.

Fractional Odds (Traditional UK Format)

Fractional odds are commonly used in horse racing and traditional UK bookmakers. They show the profit relative to the stake.

For example:

• 5/1 means you win £5 for every £1 staked, returning £6 in total.
• 10/3 means you win £10 for every £3 staked, returning £13 in total.

Although popular, fractional odds can be harder to work with when comparing values or using matched betting tools, making decimal odds the preferred choice.

American Odds (Moneyline)

American odds are used in the US and are expressed as either positive (+) or negative (-) values:

• Positive (+) odds indicate how much profit you'd make on a £100 bet. For example, +200 means a £100 bet returns £300 (£200 profit plus the original £100 stake).
• Negative (-) odds indicate how much you need to bet to win £100. For example, -150 means you need to bet £150 to win £100.

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How to Convert Odds

For matched betting, decimal odds are best because they provide a direct payout calculation. However, if you come across fractional odds, you can easily convert them:

Decimal = (Fractional Odds) + 1

Example: 5/1 → (5 ÷ 1) + 1 = 6.00

Most UK bookmakers allow you to toggle between fractional and decimal odds in your account settings.

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How Bookmakers Set Odds

Bookmakers calculate odds based on probability, ensuring they maintain an edge (the overround). The process involves:

• Assessing probability – Estimating the likelihood of an outcome.
• Adjusting for bookmaker margin – Ensuring the bookie makes a profit regardless of the result.
• Market fluctuations – Adjusting odds based on betting patterns and new information.

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Why Decimal Odds Are Recommended for Matched Betting

• Easier to Compare – Quickly see which odds offer better value.
• Simplifies Lay Betting – Exchanges like Betfair use decimal odds.
• Essential for Calculators – Matched betting tools like oddsmatchers and profit calculators use decimal odds.
• Widely Available – Most UK bookies allow easy conversion in settings.

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