−110 pays $90.91 on $100, so it needs to win 52.38% of the time.
01 · Minus and plus
The minus price is the favourite, the plus price is the underdog
American odds always talk about $100. A minus price says how much you risk to win $100. A plus price says how much $100 wins. That is the whole rule, and it is why the favourite carries the minus sign: you pay more to back the side more likely to win.
| Price | Win on $100 | Needs to win |
|---|---|---|
| −200 | $50.00 | 66.67% |
| −110 | $90.91 | 52.38% |
| +100 | $100.00 | 50.00% |
| +150 | $150.00 | 40.00% |
| +300 | $300.00 | 25.00% |
Read the middle column first. At −200 you risk $100 to collect $50, so you need to win two of every three bets just to stand still. At +300 you collect $300, so winning one in four is enough. Neither price is good or bad on its own. A price is only cheap or expensive against the real chance of the result.
02 · Implied probability
Turn any price into a percentage
Worked example · Three prices, one scale
- −110 → 110 ÷ 210
- 52.38%
- +150 → 100 ÷ 250
- 40.00%
- −200 → 200 ÷ 300
- 66.67%
Once every price is a percentage, you can line up a spread, a moneyline and a player prop and ask the same question of each: is the real chance higher than this?
Favourite: −110 implies 52.4% before the vig comes out.
03 · Why both sides add past 100%
Two sides of one bet add up to more than 100%
Price both sides of a standard bet at −110 and each side implies 52.38%. Together that is 104.76%, not 100%. The extra is the book's margin, often called the vig or the juice. On balanced action it keeps 4.55% of every dollar bet.
This is the single most useful thing to know about odds. The percentage a price shows you is the true chance plus the book's cut. To see the fair chance, take the cut out first. Taking the book's cut out of a price shows how.
Before you bet
What this means for your next bet
- Turn the price into a percentage before you decide anything.
- Ask whether the real chance is higher than that percentage. If you cannot say why, pass.
- Compare the same bet at two or three books. The cheaper price needs fewer wins.
- Remember the percentage includes the book's cut, so a fair price is always a little better than the one you see.
Questions4 questions
What does −110 mean in betting?
It means you risk $110 to win $100, or $100 to win $90.91. The price implies a 52.38% chance, so a bet at −110 has to win more often than that to make money over time.
What does +150 mean?
A $100 bet at +150 wins $150 in profit and returns $250 in total. The price implies a 40.00% chance of winning.
Is a minus price always the favourite?
Yes. The side priced with a minus sign is the one the book thinks is more likely, which is why it pays less than even money. Two sides can both be priced with a minus sign, as at −110 on each side of a spread, when the book sees them as close to even.
How do I convert American odds to a percentage?
For a minus price, divide the number by itself plus 100: −150 is 150 ÷ 250, or 60%. For a plus price, divide 100 by the number plus 100: +150 is 100 ÷ 250, or 40%.
Responsible gaming
Dynatyze is analytics and education for people 21 and over. It is not a sportsbook and never takes a bet. Every number on this page describes the past or the arithmetic of a price; none of it promises a result, and results vary.
Set a budget before you bet and keep to it. If gambling stops being fun, help is free and confidential at 1-800-GAMBLER, and our responsible gaming page lists more ways to get support.
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Research and education only. Results vary, and nothing here promises a profit. Every number from our own data names its sample and its dates; every worked example is the arithmetic of the prices shown.