JILI77 American Odds Explained: Reading Minus and Plus Prices

American odds write every price per 100 units, with a plus or minus sign that tells you which way to read it. This page decodes both signs with worked arithmetic, so you can turn any board into stake, profit and implied chance. If you want the whole path from price to payout first, start with the full picture of how sports betting works.

American odds at a glance

American odds are built around the number 100. A minus price answers “how much must I stake to win 100?” and a plus price answers “how much do I win on a 100 stake?”

The favourite carries the minus sign and the underdog carries the plus sign. A price of +100 is even money, which equals 2.00 in decimal.

What does -110 mean?

A price of -110 means you risk 110 to win 100. Stake 110 and a win returns 110 + 100 = 210, so the profit is 100.

Scale it to any stake with one line: profit = stake x 100 / 110. A stake of 55 wins 55 x 100 / 110 = 50, and a stake of 220 wins 200.

The implied chance is the stake divided by the total return: 110 / 210 = 0.5238, or 52.38 percent. That is the break-even rate. You need to win 52.38 percent of bets at -110 just to come out level.

Why -110 appears on both sides

Books often show -110 on each side of an even game. Each side implies 52.38 percent, so the pair sums to 104.76 percent. The 4.76 percent above 100 is the book’s margin, which you pay on every ticket whichever side you pick.

What does +150 mean?

A price of +150 means a stake of 100 wins 150. The total return is 100 + 150 = 250.

A smaller stake scales in proportion: profit = stake x 150 / 100. A stake of 40 wins 60 and returns 100 in total.

The implied chance is 100 / 250 = 0.40, or 40 percent. You break even if you win 4 bets in 10 at this price.

Plus minus odds: the quick rule

Plus minus odds follow one rule. A minus sign always marks the side the book thinks is more likely, and a plus sign marks the side it thinks is less likely.

1. Minus price: implied chance = price / (price + 100), using the price without its sign. At -200: 200 / 300 = 66.67 percent.
2. Plus price: implied chance = 100 / (price + 100). At +300: 100 / 400 = 25 percent.
3. Compare the two figures against your own estimate of the chance. Bet only when yours is higher.

Converting American odds to decimal

Decimal odds are easier to compare across books, so convert before you decide. Decimal odds and the payout they imply shows the conversion from the other direction.

A stake of 100 at 1.91 returns 191, which matches the -110 ticket above after you scale by 100/110.

Using American odds with other tickets

Once you hold a bet at one price, a later price on the other side can lock in a profit or a smaller loss. Hedging bets, with a worked minus-price example shows how to size that second ticket. Read the price on the board, convert it, then size the stake from the same arithmetic you used here:

1. Read the sign and the number.
2. Convert to decimal or implied chance.
3. Size the stake before you confirm.