How to Convert Odds Into Implied Probability
ProphetAiQ Team · 2026-10-25
How to convert odds to probability? To convert odds into implied probability, you take the odds and run them through a simple formula. For negative odds…
A short explainer from ProphetAiQ: how to convert odds to probability?
How to convert odds to probability?
To convert odds into implied probability, you take the odds and run them through a simple formula. For negative odds, you divide the number by itself plus one hundred. For positive odds, you divide one hundred by the number plus one hundred. That gives you a decimal, and multiplying it by one hundred gives you a percentage. That percentage is what the sportsbook's price implies about how likely that outcome is.
But here's the part most people skip. That number isn't the true probability. It's inflated because the book builds in a margin called the vig, sometimes called the juice. The vig is how the sportsbook makes money regardless of outcome. So if you add up the implied probabilities of both sides of a bet, they won't land on exactly one hundred percent. They'll come in higher. That extra bit above one hundred is the vig.
To get closer to true probability, you have to remove the vig. The way you do that is take each side's implied probability and divide it by the total of both implied probabilities combined. That rescales both numbers so they actually sum to one hundred percent. What you're left with is called the no vig or fair probability. That's a much better estimate of how likely each side really is, stripped of the book's cut.
Let's walk through an example using simple, round numbers, just to illustrate the math. Say a coin flip style bet is priced at minus one hundred ten on one side and minus one hundred ten on the other. Using the formula, each side works out to an implied probability of about fifty two point four. Add those two together and you get roughly one hundred four point eight. That extra four point eight is the vig.
Now remove it. Take one side's number, fifty two point four, and divide it by the combined total, one hundred four point eight. That division is what rescales the price down to its fair, no vig probability. Run the same division for the other side using its own fifty two point four, and you rescale that one too. Once both sides are divided through the same combined total, they balance out evenly against each other, which makes sense given they started from identical prices.
That's the whole exercise. Odds give you a price. The formula turns that price into a raw implied probability. Removing the vig turns that raw number into something closer to a fair read of the actual chances.
At ProphetAiQ, this no vig math is part of how AiQ builds out its probability models before any pick ever gets published. Understanding it just helps you read a betting line the way the model does.
Only bet what you're comfortable losing, and treat this as one tool in your process, not a guarantee of anything. If you want to see how AiQ applies this kind of thinking to real games, head over to prophetaiq.com.