American odds explained: this betting format shows either how much profit a 100-unit stake could make or how much you need to stake to win 100 units. Positive American odds apply to an underdog or less likely outcome, while negative American odds usually represent the favorite.
What do American odds mean?
American odds, also called moneyline odds, are commonly written with a plus or minus sign. The number after the sign describes the relationship between your stake and the potential profit.
- Positive odds: +150 means a 100-unit stake would produce 150 units of profit if the bet wins. Your total return would be 250 units, including the original stake.
- Negative odds: -150 means you need to stake 150 units to make 100 units of profit. A winning 150-unit bet would return 250 units in total.
The stake does not have to be 100 units. The same ratio applies to any amount, although the exact payout may be rounded by the bookmaker.
How to calculate an American odds payout
For positive American odds, use this formula:
profit = stake × odds ÷ 100
For negative American odds, use:
profit = stake × 100 ÷ absolute odds
For example, a 20-unit stake at +250 would generate 50 units of profit, giving a total return of 70 units. A 20-unit stake at -125 would generate 16 units of profit, giving a total return of 36 units.
These calculations describe the potential return before any applicable taxes, fees, limits, or account-specific bookmaker rules.
American odds and implied probability
Implied probability is the chance suggested by the quoted odds. It is not a guarantee that the outcome will happen, and bookmaker margins mean that the probabilities in a market may add up to more than 100%.
For positive odds, the formula is:
implied probability = 100 ÷ (odds + 100)
For negative odds, use:
implied probability = absolute odds ÷ (absolute odds + 100)
At +200, the implied probability is 33.33%. At -200, it is 66.67%. Comparing implied probability with your own estimate can help you understand the price of a bet, but it does not remove uncertainty or guarantee value.
How to read favorites and underdogs
A negative line such as -180 identifies the favorite in a typical two-way market. The bookmaker expects that outcome to be more likely than the opposing selection. A positive line such as +180 identifies the underdog.
Being the favorite does not mean a team or player must win. It means the odds require a larger stake for a smaller potential profit. An underdog offers a larger potential profit relative to the stake, but its implied probability is lower.
American odds compared with decimal odds
Decimal odds show the total return for each unit staked, including the original stake. American odds focus on the profit relationship around a 100-unit reference point.
To convert positive American odds to decimal odds, use:
decimal odds = 1 + (American odds ÷ 100)
To convert negative American odds, use:
decimal odds = 1 + (100 ÷ absolute American odds)
For example, +150 equals decimal odds of 2.50, while -150 equals approximately 1.67. The decimal format can be easier for comparing returns across bookmakers, while American odds may be more familiar on sportsbooks that use the moneyline format.
Common mistakes with moneyline odds
- Confusing profit with total return: the stake is added back to the profit when calculating the final payout.
- Assuming a favorite is certain to win: negative odds describe price and probability, not certainty.
- Ignoring the market type: a moneyline may include overtime, a draw option, or other rules depending on the sport and bookmaker.
- Comparing prices without checking the same selection: a full-game line and a first-half line are different markets.
- Overlooking the bookmaker margin: implied probabilities are not always fair probabilities because the odds include a built-in margin.
Frequently asked questions about American odds
What does +100 mean in American betting odds?
+100 means a 100-unit stake would produce 100 units of profit, for a total return of 200 units. It is equivalent to decimal odds of 2.00.
What does -110 mean?
-110 means a 110-unit stake would produce 100 units of profit. A 10-unit stake would produce approximately 9.09 units of profit, before any deductions.
Are American odds the same as moneyline odds?
Often, yes. Many sportsbooks use “moneyline” to describe a market quoted in American odds, particularly for two-way sports outcomes. The market rules still need checking because a moneyline can differ between sports.
Which American odds are better?
That depends on the same selection being compared. A higher positive price offers more potential profit, while a less negative price requires less stake for the same nominal profit. Compare equivalent markets, confirm the rules, and only risk money you can afford to lose.
Understanding American odds helps you see both the potential payout and the probability implied by a bookmaker’s price. It should support careful comparison, not encourage chasing losses or betting beyond a fixed budget.