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Enter a price and this turns it into the win chance that price stands for. Enter both sides of the same bet and it also shows what the sportsbook is keeping, plus the two fair numbers that add up to 100%. Every step of the math is printed next to the answer, so you can check it by hand.
Start here
Odds of -150 mean you risk $150 to win $100. Odds of +130 mean you risk $100 to win $130. Turn either one into a percentage and you get the win chance that price stands for. For -150 it is 150 divided by 250, which is 60%. For +130 it is 100 divided by 230, which is about 43.5%. Decimal odds take one step instead of two: divide 1 by the price, so 1.91 is about 52.4%.
Now the part that trips people up. Add both sides of the same bet together and you should get 100%, because one of them has to happen. You do not. You get about 103.5%. Nothing has a 103.5% chance of happening, so that extra 3.5% is not a chance at all. It is the sportsbook's cut, built into both prices. It has several names, and you only need one of them: the vig.
That is why 60% is not really the favorite's chance. It is the favorite's chance with part of the cut stuck to it. To get the number without the cut, divide each side by the total: 60% divided by 103.5% is 58.0%, and 43.5% divided by 103.5% is 42.0%. Those two add up to 100%. That pair is what a decision should be built on. A calculator that hands you 60% and stops has handed you a number with the house's cut still inside it.
One limit, stated plainly rather than buried at the bottom. This is a math tool. It converts a price into a chance and shows you what the sportsbook is keeping. It does not know which side wins, and nothing on this page is a suggestion to bet money on anything.
Worked example
A coin-flip bet priced -110 on both sides shows the same thing with a bigger cut. Each side converts to 52.4%, the pair adds up to 104.8%, and the cut is 4.8%. Read that back: to break even on a 50/50 event at that price, you have to be right 52.4% of the time.
Last thing worth saying. Taking the cut out tells you what the price says once the house's take is removed. It does not tell you the price is right. 58% is still the market's opinion. It is just the market's opinion with nothing added on top.
Asked & answered
It is the win chance that a price stands for. Odds of -150 mean you would risk $150 to win $100, and that works out to a 60% chance: 150 divided by 250. Odds of +130 mean you would risk $100 to win $130, which is about 43.5%: 100 divided by 230. Decimal odds take one step instead of two, because you divide 1 by the price, so 1.91 is about 52.4%. It tells you what the price says. It does not tell you what will happen.
Because the sportsbook takes a cut, and the cut is built into both prices. Two sides of one bet should add up to 100%, since one of them has to happen. A real pair of prices like -150 and +130 adds up to about 103.5% instead. Nothing has a 103.5% chance of happening, so that extra 3.5% is not a chance at all. It is the house's take, and the house keeps it whichever side wins.
The vig is the name for that extra amount over 100%. You will also see it called the juice, the margin or the overround; they all mean the same thing. What it costs you is easiest to see on a coin-flip bet priced -110 on both sides. Each side converts to 52.4%, the pair adds up to 104.8%, and the vig is 4.8%. That price is asking you to be right 52.4% of the time to break even on a 50/50 event.
Convert both sides, add them up, then divide each side by that total. For -150 and +130: the two sides are 60% and 43.5%, the total is 103.5%, and dividing each by 103.5% gives 58.0% and 42.0%. Those two add up to 100%, which is what a pair of chances should do. This calculator does the division for you and prints each step so you can check it.
Yes. It runs in your browser, with no login and no signup. Enter one price to convert it. Enter both sides to also see the sportsbook's cut and the two fair numbers that add up to 100%.
More free tools live on the tools hub. If it's fantasy decisions you're working on, the consensus rankings show every player's real finish with the scoring math visible, the same show-your-work approach this page takes with odds. Want that same show-your-work approach for football context? Scout is the intended question surface; its current public availability remains unverified.
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