Convert odds between American, decimal, fractional and implied probability.
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Odds express the same thing in three different formats: American (‑150, +200), decimal (1.67, 3.00) and fractional (2/3, 2/1). All of them describe what a bet pays and what probability the book is implying.
Implied probability is simply 1 ÷ decimal odds, expressed as a percentage. Decimal odds of 2.00 imply 50%; 1.67 implies about 60%. Comparing that number with your own estimate is how you find value.
The three formats come from three markets: American from the United States, decimal from Europe and much of Latin America, and fractional from the United Kingdom. Comparing two books that quote differently needs a common unit, and that unit is decimal, because it's the only one you multiply straight by your stake.
American odds have one formula per sign and a gap in the middle: no American price exists between ‑100 and +100. Even money is +100, which is 2.00 in decimal, and anything paying less than that goes negative. So ‑150 is 1.667 decimal and 60% implied; +200 is 3.00 and 33.33%.
American is also a coarser grid, because it moves in whole numbers. Decimal 1.905 and decimal 1.913 both display as ‑110, and there are 80 cents of profit per $100 staked between them. When you compare the same line at two books quoting different formats, the real gap can be wider than the American number shows.
Informational tool only. Not a sportsbook and not investment advice.