American odds, also called moneyline odds, are the standard format in the United States and you may come across them when betting on US sports. This guide explains American odds, how the positive and negative numbers work, and how they compare with UK formats. It is general information and not betting advice, so always gamble responsibly and only stake money you can comfortably afford to lose.
What American odds are
American, or moneyline, odds are shown as a number with a plus or minus sign, such as +200 or -150. They are based around a stake or win of 100 units, and the sign tells you whether the outcome is an underdog or a favourite. Understanding that American odds revolve around 100, with the plus or minus sign indicating underdog or favourite, is the starting point for reading this format, which looks quite different from UK fractions and decimals.
Positive odds
Positive American odds, like +200, show how much profit you would win on a 100 unit stake. So +200 means a 100 pound stake wins 200 pounds profit, plus your stake back. The bigger the positive number, the bigger the underdog and the larger the potential profit. Understanding that positive odds tell you the profit on a 100 stake helps you read underdog prices, and that a higher positive figure means a less likely outcome paying more if it wins.
Negative odds
Negative American odds, like -150, show how much you must stake to win 100 units of profit. So -150 means you stake 150 pounds to win 100 pounds profit, plus your stake back. The bigger the negative number, the stronger the favourite. Understanding that negative odds tell you the stake needed to win 100 helps you read favourite prices, and that a larger negative figure means a more likely outcome paying less relative to your stake.
Reading positive odds
To read positive odds, take the number as your profit per 100 staked, then scale to your actual stake. At +250, a ten pound stake wins twenty-five pounds profit (a quarter of 100), returning thirty-five pounds total. Understanding how to scale positive odds to your stake lets you work out returns on underdogs, and shows that positive American odds work much like long fractional or decimal odds, just expressed around a base of 100.
Reading negative odds
To read negative odds, the number is what you stake to win 100. At -200, you stake 200 to win 100, so a ten pound stake wins five pounds profit, returning fifteen pounds. The maths is the reverse of positive odds. Understanding how to work out returns from negative odds lets you read favourite prices, and shows that the stronger the favourite, the more you must risk to win a given amount, just as with short fractional or decimal odds.
Converting to decimal
You can convert American odds to decimal, which UK bettors often find easier. For positive odds, divide by 100 and add one: +200 becomes 3.0. For negative odds, divide 100 by the number (ignoring the sign) and add one: -200 becomes 1.5. Our guide on fractional vs decimal odds covers decimals. Understanding how to convert American odds to decimal lets you turn an unfamiliar format into one you can read at a glance and compare easily.
Converting to fractional
American odds also convert to fractions. Positive odds become the number over 100, simplified: +200 is 200/100, or 2/1. Negative odds become 100 over the number, simplified: -200 is 100/200, or 1/2. Understanding these conversions lets you express American odds as the UK fractions you may be more comfortable with. In practice, most betting sites let you switch the display format, but knowing the conversions helps you understand what an American price actually means.
The favourite and underdog
In American odds, the sign instantly tells you the favourite and underdog: negative odds mark the favourite, positive odds the underdog. In a match, the stronger side has a minus price and the weaker a plus price. Understanding that the plus and minus signs identify underdog and favourite at a glance is one advantage of the format, making it quick to see which outcome is rated more likely without any calculation.
Why UK bettors see them
UK bettors most often encounter American odds when betting on US sports, such as American football, basketball, baseball or ice hockey, where the format is standard. Some international sites also display them. Understanding that you are most likely to meet American odds on US sports helps you know when to expect them, and reassures you that you can simply switch most sites to decimal or fractional if you prefer a more familiar format.
Comparing the formats
American, fractional and decimal odds all express the same prices differently. +200 equals 2/1 equals 3.0; -200 equals 1/2 equals 1.5. None is more accurate; they are conventions. Our guide on how to read betting odds covers reading prices. Understanding that the three formats are interchangeable, just like fractions and decimals, means American odds need not intimidate you, as they describe the same likelihood and payout you already understand.
Implied probability
Like all odds, American odds imply a probability. A -200 favourite implies about a 67 per cent chance, while a +200 underdog implies about 33 per cent. Our guide on implied probability explains converting odds to percentages. Understanding that American odds, like any others, can be turned into a percentage chance helps you read what the price suggests, and reminds you that the bookmaker's margin is built in, just as with UK formats.
American odds at a glance
To summarise reading American odds quickly: a minus sign means a favourite and tells you the stake needed to win 100, while a plus sign means an underdog and tells you the profit on a 100 stake. The bigger the minus number, the stronger the favourite; the bigger the plus number, the longer the underdog. Our guide on how to read betting odds covers reading prices generally. Understanding this at-a-glance summary means you can interpret any American price without a calculator, simply reading the sign for favourite or underdog and the number for the scale of the stake or profit involved.
Betting responsibly
Whatever the format, the odds favour the bookmaker, so treat betting as entertainment, not income. Set a budget, stake only what you can afford, and never chase losses. Our guide on how to gamble responsibly has practical tools. Understanding American odds is useful if you bet on US sports, but the format does not change the fundamentals, so keep your betting within your means whichever way the odds are shown.
In short
American, or moneyline, odds use a plus or minus sign around a base of 100. Positive odds like +200 show the profit on a 100 stake (an underdog), while negative odds like -150 show the stake needed to win 100 (a favourite). They convert easily to decimal and fractional formats: +200 equals 3.0 or 2/1. You will mostly meet them on US sports, and like all odds they imply a probability and include the bookmaker's margin, describing the same likelihood and payout in a different style. Most sites let you switch to decimal or fractional if you prefer. Always gamble responsibly.
Explore more in our Betting Odds Explained guides.