Fractional and Decimal Odds: Reading and Converting Both

The short answer

Fractional odds show potential profit relative to your stake; decimal odds show the potential total return, including the stake. To convert a fraction to decimal odds, divide the first number by the second and add 1. To convert back, subtract 1 and express the result as a fraction.

How the two formats work

Odds describe a betting price, but each format presents it differently. Before calculating a return, it helps to separate three terms:

• Stake: the amount placed on the bet.
• Profit: the amount won beyond the stake.
• Total return: the stake plus the profit on a winning bet.

The calculations in this guide concern straightforward winning back bets: bets placed on a selection to win. They describe potential returns, not guaranteed outcomes.

Reading fractional odds

Fractional odds are written as two numbers separated by a slash and read as one number “to” the other. The first number is the potential profit and the second is the stake in the ratio. The numbers describe a relationship; they do not mean you have to stake the exact amount shown after the slash.

To calculate potential profit on a winning bet, multiply your stake by the first number, then divide by the second. Add the stake to that profit to find the total return.

If the first number is smaller than the second, the price is called odds-on: the potential profit is less than the stake. Equal numbers mean even money, where potential profit equals the stake. When the first number is larger, the price is odds-against, with potential profit greater than the stake. None of these labels tells you what the result will be.

Reading decimal odds

Decimal odds use one number. Multiply the stake by the decimal price to find the potential total return on a winning bet. That total already includes the stake, so subtract the stake if you want to identify the profit alone.

The distinction is important: a decimal price is not simply the amount of profit per pound. Adding the stake again after multiplying by the decimal price would count it twice.

Converting between formats

To convert fractional odds to decimal:

1. Divide the first number by the second.
2. Add 1 to include the stake in the decimal price.

To go in the other direction, subtract 1 from the decimal price. Express the result as a fraction, simplifying it if possible. Converting the display does not itself change the price or what must happen for the selection to win.

Worked example: the same price in both formats

Example: A £4 cash stake is placed on a single back bet at fractional odds of 11/4. The following calculations show what happens if that bet wins; they do not predict the result.

Both formats describe the same price. In the fractional calculation, the profit is found first and the stake is added afterwards. In the decimal calculation, multiplying by 3.75 gives the total return directly.

Bookmakers’ rules: what to check

The odds format tells you the price, but it does not provide every condition for accepting or settling a bet. The Gambling Commission says licensed operators’ rules must cover core matters including when bets are void and how errors are treated. Read the applicable rules before placing a bet, particularly the terms for the market and selection you are considering.

Check what must happen for the bet to settle as a win, and what the rules say about void bets and errors. If the stake comes from a promotion rather than your own cash, check those terms too: the simple cash-stake calculation above may not describe the return.

Also check whether commission applies. For example, Betfair states that its Exchange winnings are subject to commission. The worked return above is an arithmetic illustration and does not deduct commission; the applicable operator terms determine what charges, if any, affect a particular bet.

Common mistakes and how to avoid them

Confusing return with profit

A winning total return includes the original stake. Fractional odds express profit relative to that stake, while decimal odds include it in the price calculation. Write down which figure you are calculating before you start, then add or subtract the stake only where needed.

Treating an implied percentage as a prediction

A price can be converted into an implied percentage. For fractional odds, divide the second number by the sum of both numbers, then multiply by 100. For decimal odds, divide 100 by the decimal price.

Example: At 11/4, the calculation is 4 ÷ (11 + 4) × 100 = approximately 26.67%. At the equivalent decimal price of 3.75, it is 100 ÷ 3.75 = approximately 26.67%. This expresses the price as a percentage; it does not guarantee or predict the result.

Expecting a rounded price to convert back exactly

A decimal display may round a longer figure. Example: 13/8 converts to 13 ÷ 8 + 1 = 2.625, which may be displayed as 2.63. Reversing the rounded display gives 2.63 − 1 = 1.63 = 163/100, rather than exactly 13/8. The difference comes from rounding, so retain the unrounded figure when checking an exact conversion.

Related guides to read next

For more on reading prices, browse Odds Explained. If you want to understand how a wager settles after you have read its price, see Singles, Doubles and Accumulators: How Multiples Settle. For promotional stakes, explore Free Bet Terms.