American Odds Explained: what +400 and −150 mean

Plus odds: the profit on a $100 bet

+400 means a $100 bet wins $400 in profit, so you get $500 back in total. A $25 bet at +400 wins $100. Plus odds are used for outcomes the book sees as less likely than not.

Minus odds: what you risk to win $100

−150 means you risk $150 to win $100 in profit, getting $250 back. A $30 bet at −150 wins $20. Minus odds are used for favorites.

A worked $20 example

Say you bet $20 at +400. Divide 400 by 100 to get 4, multiply by $20, and your profit is $80: you get $100 back. Now bet $20 at −150. Divide 100 by 150 to get about 0.667, multiply by $20, and your profit is about $13.33: you get $33.33 back. Put both legs in one parlay and the decimal odds multiply: 5.00 × 1.667 is about 8.33, or +733, so $20 returns about $166.67 if both win.

Implied probability

For plus odds, the implied probability is 100 ÷ (odds + 100). +400 is 100 ÷ 500, or 20%. For minus odds, it is odds ÷ (odds + 100) using the number without its sign: −150 is 150 ÷ 250, or 60%.

Add the implied probabilities of both sides of a bet and you'll usually get more than 100%. The extra is the book's margin, often called the vig. At −110 on both sides, each side implies about 52.4%, so the pair adds up to about 104.8%.

Converting to decimal odds

Decimal odds include your stake. For plus odds, divide by 100 and add 1: +400 becomes 5.00. For minus odds, divide 100 by the number and add 1: −150 becomes about 1.67. Multiply your stake by the decimal odds to get your total return.

Try it

The odds converter turns any American, decimal or fractional price into the others and shows the implied probability, and the parlay calculator does the multiplication for you.

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