American, Decimal, and Fractional Odds Explained
American Odds (Moneyline Format)
American odds, also called moneyline odds, are the standard format on most U.S. sportsbooks and the format most UFC bettors are used to seeing. They’re shown as either a positive or negative number relative to a $100 bet.
Negative numbers (favorites). A -150 line means you need to bet $150 to win $100 in profit. The bigger the negative number, the heavier the favorite.
Positive numbers (underdogs). A +130 line means a $100 bet would win $130 in profit. The bigger the positive number, the bigger the underdog.
American odds are intuitive once you’re used to them, but they don’t scale linearly, which can make quick mental comparisons between two lines harder than it looks.
Decimal Odds (European Format)
Decimal odds are common outside the U.S. and on betting exchanges and odds comparison tools, and they’re arguably the simplest format to do quick math with. A decimal number represents your total return per $1 wagered, including your original stake.
A decimal of 1.67 means a $100 bet returns $167 total if it wins ($67 profit plus your $100 stake back). A decimal of 2.30 means a $100 bet returns $230 total. Anything below 2.00 represents a favorite, and anything above 2.00 represents an underdog, which makes decimal odds easy to scan at a glance without doing conversion math.
Fractional Odds (UK Format)
Fractional odds are traditional in the UK and still show up on some international books and in older betting media. They’re written as a fraction like 4/1 or 2/7, representing profit relative to your stake.
A fraction of 4/1 (“four to one”) means a $100 bet wins $400 in profit. A fraction of 2/7 (“two to seven”) means a $100 bet wins about $28.50 in profit, since the fighter is a heavy favorite. Fractional odds are the least common format for U.S.-based UFC bettors to encounter, but they still appear in some international betting content and older combat sports commentary.
| Format | Favorite Example | Underdog Example |
|---|---|---|
| American | -150 | +130 |
| Decimal | 1.67 | 2.30 |
| Fractional | 2/3 | 13/10 |
The exact math: to convert American favorite odds to decimal, divide 100 by the absolute value of the American number and add 1. To convert American underdog odds to decimal, divide the American number by 100 and add 1. Most bettors don’t do this math by hand in practice — most odds comparison tools and sportsbook settings let you toggle between formats directly, which is the easier approach day to day.
Why This Matters for UFC Betting
Line shopping across multiple sportsbooks is one of the simplest ways to improve your long-term results, and that often means comparing odds displayed in different formats if you’re checking an international book or an odds aggregator. Being able to quickly recognize whether 1.91 and -110 represent the same price (they do) means you can actually compare value across books instead of getting confused by the display format. This becomes especially relevant when using an odds comparison tool that may default to a format you’re not used to.
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Frequently Asked Questions
American odds are the standard on most U.S.-facing sportsbooks and the format most UFC betting content uses, but decimal odds are common on odds comparison sites and international books.
No format changes the actual payout — they’re just different ways of displaying the same price. Decimal odds are often considered the easiest for quick mental math since the number is your total return multiplier.
Anything below 2.00 in decimal odds represents a favorite, since it means your total return (including stake) is less than double your bet. Anything above 2.00 represents an underdog.
Yes, most modern sportsbooks have a settings option to toggle between American, decimal, and fractional display, which is generally easier than manually converting between formats.
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About the Author
Rob Brown has been betting on MMA professionally since 2015. Every pick is publicly recorded and independently verified — no cherry-picking, no deleted bets. His full record is tracked at betMMA.tips and bettin.gs.
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