How to read American odds

What do +150 and -200 actually mean?

A positive number is what you win on 100 staked. A negative number is what you must stake to win 100. +150 returns 150 profit on 100; -200 needs 200 to win 100.

Converting to decimal makes them comparable, and converting to implied probability makes them meaningful:

+150 is decimal 2.500 and implies 40.00%. -200 is decimal 1.500 and implies 66.67%. -110, the standard price, is decimal 1.909 and implies 52.38% — which is why a coin-flip bettor at -110 loses steadily.

The trap is calling that implied number a probability. It is vig-inclusive: it is what the price asserts, and across a market those assertions add to more than 100%. Treating it as a fair probability without devigging first is the most common way to invent an edge that is not there. Convert →