Decimal Odds Calculator: Turn Prices Into Potential Returns

A decimal odds calculator does one job: it multiplies your stake by the decimal price to give the total return, and subtracting the stake leaves your profit. At 2.50, a £10 winning bet returns £25 in total and £15 in profit. Use the calculator below, then read on to check the sums by hand, convert between formats, find the bookmaker’s margin and see where the simple formula stops working.

How does a decimal odds calculator work?

It applies two sums: stake × decimal odds = total return, and total return − stake = profit. Decimal odds already include your stake, which is why the total return is always larger than the profit.

Doubling the stake doubles both figures. A short price such as 1.50 pays less per pound but wins more often. A long price such as 6.00 pays more but only needs to win about one time in six to break even.

Read the bet slip carefully. Many slips show “potential return”, which includes your stake, so £25 on a £10 bet is £15 profit. Our Betting Tools page has calculators that show both numbers.

How do you work out the stake or price you need?

Rearrange the same formula. The stake needed for a target profit is profit ÷ (decimal odds − 1), and the price needed is target total return ÷ stake.

• Stake for a target profit: to make £100 profit at 3.50, stake £100 ÷ 2.50 = £40. Check: £40 × 3.50 = £140 back, so £100 profit.
• Price for a target return: to turn £20 into £50 in total, you need £50 ÷ £20 = 2.50.

How do you convert decimal odds to fractional and American odds?

Decimal odds minus 1 gives the profit per £1 staked, which is the fraction used in fractional odds. American (moneyline) odds show the profit on a 100-unit stake when positive, or the stake needed to win 100 when negative.

To work these out yourself:

• Fractional to decimal: divide the top number by the bottom, then add 1. For 7/4, 7 ÷ 4 + 1 = 2.75.
• Positive American to decimal: divide by 100, then add 1. For +150, 150 ÷ 100 + 1 = 2.50.
• Negative American to decimal: divide 100 by the number without the minus sign, then add 1. For -150, 100 ÷ 150 + 1 = 1.67 (rounded).
• Decimal to fractional: subtract 1 and write the result as a reduced fraction. For 3.50, 2.50 becomes 5/2.
• Decimal to American: at 2.00 or above, (decimal − 1) × 100 with a plus sign. Below 2.00, −100 ÷ (decimal − 1).
• Hong Kong to decimal: add 1, because Hong Kong odds show profit only.

Check the fractional example. A 7/4 winner on a £4 stake pays £7 profit, so £11 comes back, which matches £4 × 2.75. A common mistake is reading 3.00 as “3/1”. It is 2/1, because the decimal figure includes the stake.

Rounding can move the answer slightly. 5/6 is exactly 1.8333, so £100 returns £183.33, but a site showing it as 1.83 would give £183.00. Check which figure your bookmaker settles on. For racing prices, our horse racing odds guide goes deeper on fractions, and the football match odds guide covers three-way prices.

What does a decimal price say about the chance of winning?

Divide 1 by the decimal odds and multiply by 100 to get the implied probability, the chance the price needs to be right for you to break even. At 2.50 that is 1 ÷ 2.50 × 100 = 40%.

This is not a forecast. It is the bookmaker’s price converted into a percentage, and that price includes a margin. Your job is to judge whether the real chance is higher or lower than the percentage implied.

Turn your own estimate into a price with 1 ÷ probability. If you rate a team a 45% chance, the break-even price is 1 ÷ 0.45 = 2.22. Offered 2.50, a £10 stake would average £10 × 0.45 × 2.50 = £11.25 back by your estimate, but only if your 45% is right. Most bettors overrate their own estimates, so treat this as a sense check, not a promise.

How do you spot the bookmaker’s margin?

Add up the implied probabilities of every outcome in a market. If the total is above 100%, the excess is the bookmaker’s margin, also called the overround or vig.

Take a tennis match priced at 1.80 and 2.10. The implied probabilities are 55.6% and 47.6%, which total 103.2%, so the margin is about 3.2 percentage points. A fair, margin-free market would total exactly 100%.

To strip the margin out roughly, divide each probability by the total. That gives 53.8% and 46.2%. It is a useful comparison between bookmakers, but it assumes the margin is spread evenly, which is not always true. A higher total means you pay more for the same bet, so compare prices before you bet. Our sports betting guide explains markets and multiples in more detail.

How do decimal odds work for accumulators?

Multiply the decimal odds of every selection together, then multiply by your stake. Decimal odds are the easiest format for this because no conversion is needed.

Take three selections at 2.00, 1.50 and 3.00. The combined price is 2.00 × 1.50 × 3.00 = 9.00. A £10 stake returns £90 in total, which is £80 profit, but only if all three win. One loss loses the whole bet.

The margin compounds too. Four selections each priced at 1.91 multiply to 13.31, so £10 returns £133.09. Four true 50% chances would pay 2.00 each, which multiplies to 16.00 and returns £160. The more legs you add, the more of that margin you pay.

How do decimal odds work on a betting exchange?

Exchange prices are always decimal and always include the stake, but commission comes off your winnings and lay bets carry a liability. Betfair’s help pages give the standard example: a £10 back bet at 6 returns £50 profit plus the £10 stake.

• Commission: Betfair charges commission on net winnings in a market and none on a net loss. Its own example takes £400 of net winnings at a 5% market base rate with a 40% discount, which gives £12 commission. Your actual rate depends on your region and package. At a flat 5%, a £10 back bet at 2.50 earns £15 profit, less £0.75, leaving £14.25.
• Lay liability: when you lay, the most you can lose is the backer’s stake × (odds − 1). Laying £10 at 7.00 risks £10 × 6 = £60 to win £10.

Exchange prices also move in set steps. Betfair’s developer documentation lists the standard increments below, so you cannot ask for 2.51 or 3.01.

When does the simple formula not apply?

Stake × odds covers a single winning bet at fixed odds. These situations change the answer:

• Free bets: most free bets are “stake not returned”, so the free stake is not paid back. A £10 free bet at 2.50 returns £15, not £25. See our free bet calculator guide.
• Each-way bets: these are two bets, one on the win and one on the place. A £5 each-way bet (£10 staked) at 5.00 with one-quarter odds for three places pays £25 on the win part. The place part pays at 1 + (4 × ¼) = 2.00, so £10. A winner returns £35 in total. A horse that only places returns £10, which is your total stake back. See our guide to extra place races.
• Non-runners in racing: a withdrawn horse can trigger a Rule 4 deduction, which cuts the winnings on your remaining bets. Use our Rule 4 calculator to adjust returns.
• Void bets and pushes: the stake is normally returned. In an accumulator a void leg is usually treated as odds of 1.00, so the other legs still count.
• Tote and pool betting: dividends depend on the final pool, so an earlier calculation is only an estimate.

Which price do you use: the one you took or the current one?

On a standard fixed-odds bet, the price on your bet slip is the one that is paid, whatever the odds do afterwards. The exception is a bet placed at starting price (SP), where the price is set when the race starts.

When comparing bookmakers, check that the market, line and settlement rules match. A price of 2.10 on a different handicap line is not better than 2.00 on another.

Before you trust a payout figure

• Is the figure total return or profit?
• Is the stake returned? It is not on a “stake not returned” free bet.
• Does the bet have an each-way, Rule 4, void, rounding or commission adjustment?
• Are all your prices in the same format?
• Does the implied probability still look reasonable once the margin is allowed for?

Frequently asked questions

How do I calculate winnings from decimal odds?

Multiply your stake by the decimal odds for the total return, then subtract the stake for profit. A £20 bet at 3.40 returns £68 in total, which is £48 profit.

Do decimal odds include the stake?

Yes. Decimal odds show the total return per unit staked, including the stake itself. Fractional odds show profit only.

How do I convert decimal odds to implied probability?

Divide 1 by the decimal odds and multiply by 100. For example, 4.00 gives 1 ÷ 4 × 100 = 25%.

How do I work out accumulator returns with decimal odds?

Multiply the decimal odds of every selection together, then multiply by your stake. Selections at 2.00, 1.50 and 3.00 combine to 9.00, so £10 returns £90 if all win.

How much do I need to stake to win a set amount?

Divide the profit you want by the decimal odds minus 1. To win £100 at 3.50, stake £100 ÷ 2.50 = £40.

Why is my payout lower than the calculator showed?

Common causes are a free bet where the stake is not returned, a Rule 4 deduction, exchange commission, a void or partly settled leg, rounding, or a bet placed at starting price.