American Odds

Plus and minus prices

American odds are built around a $100 reference. A positive number shows the profit on a $100 stake; a negative number shows the stake needed to profit $100. At +150, a winning $100 bet earns $150 profit and returns $250 with the stake. At −150, you risk $150 to earn $100 profit, also returning $250 in total.

The same arithmetic scales to any stake. For a plus price, profit is the stake times the odds divided by 100: $40 at +175 earns $70. For a minus price, profit is the stake times 100 divided by the odds: $40 at −125 earns $32. The bet slip shows the exact payout before you confirm, and books may round it to the cent.

Favorites, underdogs, and even money

A minus sign marks the side the market prices as more likely to win, and the larger the number, the bigger the favorite: −300 is a heavier favorite than −150. A plus sign marks an underdog, and +400 is a longer shot than +150. Even money is +100, which pays $100 on a $100 stake. A −100 price would pay exactly the same, so you will rarely see it listed.

Nothing sits between −100 and +100, so prices near even money can look farther apart than they are. Bettors describe the gap between −105 and +105 as ten “cents,” even though the numbers look 210 apart. Converting to probability or decimal odds makes small differences easier to compare.

Convert American odds to implied probability

Implied probability is the win rate at which a bet at that price breaks even. For a negative price, divide the odds by the odds plus 100: −150 becomes 150 ÷ 250 = 60.00%. For a positive price, divide 100 by the odds plus 100: +150 becomes 100 ÷ 250 = 40.00%. The table shows common prices; the total return on a win is the profit plus the $100 stake.

Applied to both sides of one market, implied probabilities add up to more than 100%. A game priced −150 on one team and +130 on the other implies 60.00% and 43.48%, a total of 103.48%. The extra 3.48 points is the book’s margin, which the no-vig odds guide shows how to remove.

Convert American odds to decimal

Decimal odds express the total return per $1 staked, which makes them convenient for multiplying parlay legs and comparing prices. For a positive price, divide by 100 and add 1: +175 becomes 2.75. For a negative price, divide 100 by the odds and add 1: −125 becomes 1.80, and −110 becomes 1.909, usually displayed as 1.91.

That rounding can matter when prices are close. Decimal 1.91 converts back to about −109.9, not exactly −110, so convert from the original quote rather than from a rounded display. The decimal odds guide covers the reverse conversion.

Read the price before the team

A minus price is not a safer bet in any useful sense; it is a smaller payout that requires a higher win rate. A bettor who backs −200 favorites must win two of every three bets to break even, while one who backs +200 underdogs breaks even by winning one in three. Whether either bet is worth making depends on how the real chance compares with that break-even rate, which is the subject of the expected value guide.