Understanding how odds work is a key part of placing a bet, no matter the market. If you are used to decimal or fractional odds, the American format can look a bit unfamiliar at first, but it follows a clear logic.
This guide walks through what the positive and negative numbers mean, how payouts are calculated, how to convert between formats, and how American odds fit into parlays and multiples. You will also find quick examples and a short checklist of common mistakes to avoid, so everything clicks into place.
What Are American Odds And How Do They Differ From Decimal Or Fractional Odds?
American odds, also called moneyline odds, use positive and negative numbers to show potential profit or required stake.
- A positive number (for example, +150) shows how much profit could be made from a £100 stake.
- A negative number (for example, -200) shows how much needs to be staked to make £100 profit.
This contrasts with decimal odds, which show the total return for a £1 bet including the stake, and with fractional odds, which show profit relative to the stake (for example, 5/1).
Knowing that basic structure sets you up for the next step: understanding what those plus and minus signs tell you in practice.
What Does A Positive Or Negative Number Mean In American Odds?
The sign in front of the number guides how the payout is worked out and also hints at how the market has priced the outcome.
A positive number such as +200 means the potential profit from a £100 stake is £200. So a £10 stake at +200 would return £30 in total, which is £20 profit plus the £10 stake. A negative number such as -150 means £150 must be staked to make £100 profit. On a smaller stake of £10 at -150, the profit would be £6.67 and the total return £16.67.
If you have the sign straight, the rest of the maths falls into place.
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Do American Odds Include The Stake?
American odds quote profit only. The original stake is not included in the number you see. When a bet wins, the payout is the profit shown by the odds plus the stake returned.
For example, a £20 bet at +120 produces £24 profit and a £44 total return. A £20 bet at -200 produces £10 profit and a £30 total return. This is different from decimal odds, which show the full return in one number.
With that cleared up, the next question is how to do the calculations quickly and compare options across formats.
How Do I Calculate My Payout From American Odds?
The calculation differs for positive and negative odds, but both follow a simple pattern once you know it. If you would rather not do the maths, use our odds converter and payout calculator to get the numbers instantly.
Converting Positive Odds To Decimal And Probability
For positive odds (for example, +150), profit scales in direct proportion to the stake.
To find total returns from a stake:
Payout = (Stake x (Odds/100)) + Stake
For example, with +200 odds and a £10 stake:
Payout = (£10 x (200/100)) + £10 = (£10 x 2) + £10 = £20 + £10 = £30
To convert positive American odds to decimal odds:
Decimal Odds = (American Odds / 100) + 1
Probability (the implied chance of the outcome) can be calculated like this:
Probability (%) = 100 / (Odds + 100) x 100
For +200 odds: 100 / (200 + 100) = 100 / 300 = 0.33 (33.3%)
Converting Negative Odds To Decimal And Probability
For negative odds (for example, -150), the number shows the stake needed to make £100 profit.
To work out total returns:
Payout = (Stake / (|Odds| / 100)) + Stake
For example, with -150 odds and a £15 stake:
Payout = (£15 / (150/100)) + £15 = (£15 / 1.5) + £15 = £10 + £15 = £25
To convert negative American odds to decimal odds:
Decimal Odds = (100 / |American Odds|) + 1
Probability for negative odds:
Probability (%) = |Odds| / (|Odds| + 100) x 100
For -150 odds: 150 / (150 + 100) = 150 / 250 = 0.6 (60%)
Once you can translate odds into returns and implied chances, comparing prices across markets becomes far easier.
How Do You Use Implied Probability To Compare Odds?
Implied probability converts any odds format into a percentage that reflects the chance suggested by the price. It allows like-for-like comparisons between different offers.
For example, +150 implies 40.0% (100 / (150 + 100) x 100), while +160 implies 38.5%. If two bookmakers list the same selection at +150 and +160, the +160 line suggests a slightly lower implied chance and therefore a higher potential return for the same stake. That difference can matter over time.
Keep in mind that markets include an overround, so the implied probabilities of all outcomes in an event usually add up to more than 100%.
If you are comfortable with implied probability on single selections, the next logical step is seeing how it plays out when you combine picks.
How Do Parlays And Multiples Work With American Odds?
Parlays, also known as multiples or accumulators, combine two or more selections into one bet. Every selection needs to win for the parlay to pay out.
With American odds, it is easiest to convert each selection to decimal, multiply those decimals together to get the combined price, then multiply by the stake to find the total return. Some sites also show the combined price back in American format once you have made your picks.
A quick example: combine +120 (decimal 2.20) with -150 (decimal 1.67). The combined decimal price is 2.20 x 1.67 = 3.67. A £10 stake would return £36.70 in total, which is £26.70 profit plus the £10 stake. If any leg loses, the parlay does not pay.
If you prefer to see the numbers in action before trying a parlay, single-bet examples make the mechanics clearer.
Quick Examples: Single Bets And Returns
Understanding how returns work is important for anyone placing a single bet using American odds. These short examples show how profits and total payouts are calculated.
Example 1: Positive American Odds (+180)
A £10 bet at +180 produces profit of (£10 x 1.8) = £18. The total return is £10 + £18 = £28.
Example 2: Negative American Odds (-120)
A £12 bet at -120 produces profit of (£12 / 1.2) = £10. The total return is £12 (stake) + £10 (profit) = £22.
If you are unsure about a price, our calculator will do the heavy lifting so you can check a payout before you commit.
Common Mistakes When Reading American Odds
A frequent mistake is mixing up what the signs mean. Positive odds show potential profit from a £100 stake, while negative odds show the stake required to make £100 profit. Getting the sign wrong leads to incorrect expectations about returns.
Another error is forgetting that American odds display profit only, not the total return. Always add back the original stake to find the full payout.
Parlays and multiples often trip people up. Adding odds together does not work. Convert each selection to decimal, multiply, then apply the stake to see the total return.
Confusing American odds with fractional or decimal on sites that offer multiple formats can also cause problems. It is worth checking which display setting is active before placing a bet.
