Every odds format is answering the same question — "how often should this happen?" — while dressing it up as "how much would I win?" Once you can translate any odds number into a percentage, every board in sports reads the same way. That translation is the whole skill, and it's about 30 seconds of arithmetic.
American odds come in two flavors. A minus number marks the favorite: −150 means you must risk $150 to win $100. A plus number marks the underdog: +130 means a $100 stake wins $130. The bigger the minus number, the heavier the favorite; the bigger the plus number, the bigger the long shot.
Two formulas cover everything:
Minus odds: probability = odds ÷ (odds + 100), using the number without the sign.
−150 → 150 ÷ 250 = 60%.
Plus odds: probability = 100 ÷ (odds + 100).
+130 → 100 ÷ 230 = 43.5%.
Run the conversion on both sides of a typical line — say −110 on each team — and you get 52.4% + 52.4% = 104.8%. Real probabilities can't exceed 100%; the extra 4.8% is the operator's built-in margin, known as the vig (or juice). It's the price of the bet being offered at all.
To recover the market's true opinion, you de-vig: divide each side's implied probability by the total. 52.4 ÷ 104.8 = 50% — the market actually thinks this game is a coin flip. Whenever BleacherBots shows a "market consensus" percentage, it has already been de-vigged; you're seeing the market's opinion, not the operator's margin.
Most of the world outside the US uses decimal odds, and they're friendlier: your total return is simply stake × the decimal number, and the implied probability is 1 ÷ the decimal. Odds of 2.50 mean a $10 stake returns $25, and imply 1 ÷ 2.50 = 40%.
Here's the part that makes prediction markets refreshingly readable: the price already is the probability. A Yes contract trading at 60¢ means the market puts the outcome at about 60%. No formulas, no signs to flip — 60¢, 60%, done. The Yes and No prices on a contract add up to roughly $1, with a small gap between the best buy and sell prices (the spread) where an operator's margin would otherwise sit.
New to how these markets work mechanically? Start with our plain-English guide to prediction markets.
Our pipeline runs the same translation you just learned, every day, for every game: pull the market lines, strip the vig, and blend that consensus with our own models (margin-adjusted Elo plus Dixon-Coles). The output is one win probability per game, published as a percentage and graded in public after every final. When our model disagrees with the de-vigged market by a wide margin, the pick carries a 💎 value flag — that gap is exactly the "model vs. market" comparison this page teaches you to read.