What do negative odds mean?

Negative American odds (e.g., -150) indicate the favorite and show how much you must bet to win $100. At -150, you risk $150 to win $100. The larger the negative number, the bigger the favorite.

What do positive odds mean?

Positive American odds (e.g., +200) indicate the underdog and show how much you win on a $100 bet. At +200, a $100 bet wins $200. The larger the positive number, the bigger the underdog.

How do I convert American odds to decimal odds?

For positive American odds: Decimal = (American / 100) + 1. Example: +200 = (200/100) + 1 = 3.00. For negative American odds: Decimal = (100 / |American|) + 1. Example: -150 = (100/150) + 1 = 1.667.

What is implied probability?

Implied probability is the chance of an outcome happening as suggested by the odds. For -150 odds, the implied probability is 60% (150/250). For +200 odds, it is 33.3% (100/300). Note: implied probabilities from a sportsbook sum to more than 100% due to the vig.

Which odds format is the best?

Decimal odds are the simplest for calculating payouts (just multiply by your stake). American odds are standard in the US and make it easy to see favorites vs underdogs. Use whatever you are comfortable with - our odds converter can switch between all formats instantly.

How to Read Betting Odds: A Complete Guide

Understanding odds is the foundation of sports betting. This guide covers American, decimal, and fractional odds with conversion formulas and real-world examples.

American Odds (Moneyline)

American odds are the standard format in the United States. They are expressed with a plus (+) or minus (-) sign relative to $100.

Negative Odds (Favorites)

Shows how much you must risk to win $100.

-110Risk $110 to win $100

-150Risk $150 to win $100

-300Risk $300 to win $100

Positive Odds (Underdogs)

Shows how much you win on a $100 bet.

+100$100 bet wins $100

+200$100 bet wins $200

+500$100 bet wins $500

Decimal Odds

Decimal odds are the simplest format. They represent the total payout per $1 wagered, including your original stake. Popular in Europe, Australia, and Canada.

Formula: Payout = Stake x Decimal Odds

1.91 (same as -110)$100 x 1.91 = $191 total

2.50 (same as +150)$100 x 2.50 = $250 total

4.00 (same as +300)$100 x 4.00 = $400 total

Fractional Odds

Fractional odds are traditional in the UK and Ireland. Expressed as a fraction (e.g., 5/1, read as "five to one"), they show the profit relative to the stake.

Formula: Profit = Stake x (Numerator / Denominator)

10/11 (same as -110)$110 bet wins $100 profit

3/2 (same as +150)$100 bet wins $150 profit

5/1 (same as +500)$100 bet wins $500 profit

Conversion Formulas

From	To	Formula
American (+)	Decimal	(American / 100) + 1
American (-)	Decimal	(100 / \|American\|) + 1
Decimal	Implied Prob	1 / Decimal
American (+)	Implied Prob	100 / (American + 100)
American (-)	Implied Prob	\|American\| / (\|American\| + 100)

Use our Odds Converter to instantly convert between all formats.

Practice Scenarios

Scenario 1: NFL Game

Chiefs -175, Bills +145. The Chiefs are the favorite (risk $175 to win $100). The Bills are the underdog ($100 bet wins $145). The Chiefs' implied probability is 63.6%, the Bills' is 40.8%. Notice these sum to 104.4% - the extra 4.4% is the sportsbook's vig.

Scenario 2: NBA Total

Over 221.5 (-110), Under 221.5 (-110). Both sides at -110 is the standard "pick'em" pricing. Each side has a 52.38% implied probability (104.76% total). You need to win 52.4% of these bets to break even.