FAQ

How Do UFC Betting Odds Work? Plus and Minus Explained

By Marco Stellini · Updated

A fighter at -400 means bet $400 to profit $100; at +275, a $100 bet profits $275. This FAQ breaks down American odds, implied probability and vig for UFC

UFC odds in the US use the American (moneyline) format. A negative number shows the favorite; a positive number shows the underdog. Once you get that, the rest follows quickly.

What Do the Plus and Minus Signs Mean?

A minus sign means you have to risk more than $100 to profit $100. A plus sign means a $100 bet profits more than $100.

  • -400 favorite: bet $400 to profit $100. The sportsbook considers this fighter very likely to win.
  • +275 underdog: bet $100 to profit $275. Higher reward, lower implied chance of winning.

I find it helps to flip the math in your head. With -400, ask: "How many times do I have to bet $400 to make $100 profit?" With +275, ask: "How much do I win on a $100 shot?" That framing keeps it simple.

How Do I Calculate Implied Probability?

Implied probability tells you what chance the odds assign to a fighter winning.

  • Negative odds: divide the number by (the number + 100). So -400 → 400 ÷ 500 = 80%.
  • Positive odds: divide 100 by (the number + 100). So +275 → 100 ÷ 375 = roughly 27%.

Notice those two probabilities add up to 107%, not 100%. That gap is the vig — the sportsbook's built-in margin on every fight.

What Is the Vig (Juice)?

The vig is the commission a sportsbook takes on every bet. It's baked into the odds, not added on top. You never see it as a separate line item. It's why shopping lines across multiple books — a practice called line shopping — matters, especially on big fights.

For more on the different wager types where these odds apply, see what types of bets you can make on a UFC fight.

Do Odds Change Before Fight Night?

Yes, and they can move fast. Injury news, weight-cut reports, and heavy betting volume all shift lines. Always check the current odds right before placing your wager, not hours earlier.

To find books that post UFC lines early and offer odds boosts, check out the best UFC betting sites ranked for 2026. You can also compare UFC welcome bonuses while you're evaluating your options, and read about how rollover terms work before claiming any offer.

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Quick Reference: American Odds at a Glance

Odds Role Profit on $100 bet Implied probability
-400 Favorite $25 ~80%
-150 Moderate favorite $67 ~60%
+275 Underdog $275 ~27%

Once you're comfortable reading UFC odds, consider tracking your winnings carefully. All sports betting profits are taxable ordinary income — see how UFC betting taxes work for the details.