American odds look like a secret code until someone shows you the one rule behind them. There is only one rule, and once you have it, every price on the board reads the same way. This guide walks through it with real numbers.

A minus sign in front of a number means the side is a favorite. A plus sign means it is an underdog. The number is always measured against $100, which keeps every price on the same scale even when you bet more or less.

A price of -110 means you risk $110 to win $100. A price of -200 means you risk $200 to win $100. The bigger the number after the minus sign, the heavier the favorite, and the more you have to put up for the same $100 of profit.

A price of +150 means you risk $100 to win $150. A price of +200 means you risk $100 to win $200. The bigger the number after the plus sign, the longer the shot, and the more it pays when it comes in.

The $100 is just a yardstick. To scale a plus price, multiply your stake by the number and divide by 100. A $25 bet at +150 wins 25 times 150 divided by 100, which is $37.50, and returns $62.50. To scale a minus price, your profit is your stake divided by the number, times 100. A $55 bet at -110 wins $50.

A pick can come wrapped in stars, a "lock" label, or a sales pitch. None of those is a number you can check. The price is. Once you can read it, you can work out the one thing that matters: how often the bet has to win just to break even. That is the next step, and it starts from the price you just learned to read.

One price sits right in the middle. A bet at +100 or -100 is even money: you risk $100 to win $100, with no favorite and no underdog. As a side gets more likely, its minus number grows, and as it gets less likely, its plus number grows. The sign and the size together tell you, at a glance, both who the market favors and by how much, before you work out a single percentage.

For entertainment and education. Nothing here predicts results or recommends a bet.