Betting odds can look unfamiliar if you are used to fractional or decimal formats. American odds, sometimes called moneyline odds, use positive and negative numbers, which can take a moment to get used to.
This blog post breaks down how American odds work, why some bookmakers use them, and how they compare with other formats. You will find clear explanations and simple examples throughout.
As with any betting, keep to sensible limits and only stake what you can afford.
What Are American Odds And How Do They Work?
American odds are a way of displaying prices using positive and negative numbers. They are common in the United States and also appear on some international bookmaker sites.
A positive number (for example, +200) shows the profit from a £100 stake if the selection wins. So +200 would return £200 profit, plus the original £100 stake. A negative number (for example, -150) shows how much must be staked to earn £100 profit. In that case, a £150 stake would return £100 profit, plus the £150 stake.
This system uses £100 as a reference point, which makes it quick to estimate potential returns or the stake required.
If that baseline makes sense, the next step is understanding what the plus and minus signs tell you at a glance.
What Do Positive And Negative American Odds Mean?
American odds use the sign to signal how the price should be read.
Positive odds (such as +250) show potential profit from a £100 stake. With +250, a £100 bet returns £250 profit, plus the stake. Negative odds (such as -120) show the stake needed to make £100 profit. With -120, a £120 bet would return £100 profit, plus the stake.
In general, positive odds are attached to outcomes considered less likely, while negative odds indicate more strongly favoured outcomes.
Once the signs are clear, working out payouts becomes straightforward.
How Do You Calculate Payouts From American Odds?
Calculating payouts is simple once you know whether the odds are positive or negative.
For positive odds (e.g., +250), the number shows profit per £100 staked:
- Profit = (Stake × Odds) ÷ 100
Example: £40 at +250 gives (40 × 250) ÷ 100 = £100 profit. Total return would be £140.
For negative odds (e.g., -150), the number shows the stake needed to make £100 profit:
- Profit = (Stake × 100) ÷ |Odds|
Example: £60 at -150 gives (60 × 100) ÷ 150 = £40 profit. Total return would be £100.
Prefer a different format for quick comparisons? Converting American odds to decimal or fractional is easy.
How Do You Convert American Odds To Decimal And Fractional?
Converting depends on whether the odds are positive or negative.
For positive American odds (e.g., +200):
- Decimal = (Odds ÷ 100) + 1
Example: (200 ÷ 100) + 1 = 3.00 - Fractional = Odds ÷ 100
Example: 200 ÷ 100 = 2/1
For negative American odds (e.g., -150):
- Decimal = (100 ÷ |Odds|) + 1
Example: (100 ÷ 150) + 1 ≈ 1.67 - Fractional = 100 ÷ |Odds|
Example: 100 ÷ 150 = 2/3
Decimal odds show total return (including the stake). Fractional odds show profit relative to the stake.
Those same figures can also be read as a view of how likely an outcome is thought to be.
How Do You Work Out Implied Probability From American Odds?
Implied probability expresses the likelihood of an outcome based on the price.
For positive American odds (e.g., +200):
- Implied Probability = 100 ÷ (Odds + 100) × 100
Example: 100 ÷ (200 + 100) × 100 = 33.33%
For negative American odds (e.g., -150):
- Implied Probability = |Odds| ÷ (|Odds| + 100) × 100
Example: 150 ÷ (150 + 100) × 100 = 60%
These percentages reflect the bookmaker’s view and include margin, so probabilities across all outcomes typically add up to more than 100%.
With that in mind, it helps to see how these prices appear on actual markets.
How Are American Odds Presented On Bookmaker Markets?
On bookmaker markets using American odds, each selection has either a positive or negative number beside it.
A typical match market might show:
Team A: +180
Team B: -120
The plus sign (+) marks outcomes considered less likely, while the minus sign (-) signals a stronger favourite. The figures tie back to the £100 benchmark explained earlier, either as potential profit (+) or stake required (-).
Most sites allow a quick switch between American, decimal, and fractional formats in settings, so you can view prices in the format you find easiest.
Calculating Multiples And Parlays With American Odds
Multiples, often called parlays with American odds, combine two or more selections into one bet. Every selection must win for a return.
To estimate the payout, convert each American price to decimal, multiply the decimals together, then multiply by your stake. For example, +150 becomes 2.50 and -120 becomes 1.83. If those two are combined, 2.50 × 1.83 ≈ 4.58. A £10 stake would therefore return about £45.80, including the stake.
Adding more selections increases potential returns but also raises the risk, because the entire bet depends on every leg winning.
If you are weighing up several options, it can be useful to compare how different bookmakers price the same outcome.
How To Compare American Odds Between Bookmakers?
Comparing prices involves checking the odds offered on the same selection across different bookmakers to see where the potential return is highest.
It often helps to switch everything to a format you read quickest, such as decimal, so small differences stand out. Also look for any terms that might affect settlement, such as rule variations or market-specific conditions.
Small price differences can reflect timing, market movement, or the margin a bookmaker builds in. Comparing can improve value, but it does not change the probability of the outcome itself.
Before moving on, it is worth noting a few common pitfalls.
Common Mistakes When Reading American Odds
A few recurring errors can make American odds feel trickier than they are:
- Mixing up the signs. Positive odds show profit per £100 staked, while negative odds show the stake needed to make £100 profit.
- Forgetting to convert to a familiar format before comparing prices or calculating returns, which can lead to misreads.
- Misinterpreting implied probability and assuming a higher payout always means a greater chance of winning.
- Overlooking settlement rules or offer terms that can affect the final payout.
- Confusing total return with profit when moving between decimal, fractional, and American formats.
If gambling starts to affect your well-being or finances, seek support early. Independent organisations such as GamCare and GambleAware provide free, confidential help. With the basics in place, reading and comparing American odds should feel far more straightforward.
