Converting Odds: American, Decimal, Implied Probability
Reading American odds
A negative price is the amount you must risk to win $100: -150 means risking $150 to win $100. A positive price is the amount you win on a $100 risk: +200 means winning $200 on $100. Even money is +100.
The conversions
- Negative price: implied chance = price / (price + 100), using the price without its minus sign.
- Positive price: implied chance = 100 / (price + 100).
- Decimal odds from a negative price: 1 + 100 / price. From a positive price: 1 + price / 100.
- The chance a decimal price implies is 1 divided by the decimal odds. That chance is also the break-even win rate: win more often than it and the price paid off over time.
Check: -150 is 150 / 250 = 60.0%. +200 is 100 / 300 = 33.33%. Standard -110 needs a 52.38% win rate just to break even.
From implied to fair
An implied probability from one price still contains the book's margin. To get the market's fair chance you need both sides of the market and remove the vig (see no-vig odds). The odds calculator does each step with the numbers you type in.
Questions and answers
- How do you convert American odds to implied probability?
- For a negative price divide it (without the minus sign) by itself plus 100: -150 is 150 / 250 = 60.0%. For a positive price divide 100 by the price plus 100: +200 is 100 / 300 = 33.3%.
- What win rate does -110 need to break even?
- 52.38%. At -110 you risk $110 to win $100, so you must win 110 of every 210 bets to come out level.
- What is +100 in decimal odds?
- 2.00. Even money returns your stake plus an equal profit, so a $100 bet returns $200.
Read next
- No-vig oddsNo-vig odds, also called fair odds, are a two-sided price with the sportsbook's margin (the vig, or juice) taken out, so the two sides' chances add up to 100%.
- Player prop lineA player prop line is the number a sportsbook posts for one player's stat in one game, such as 24.5 points, with a price on the over and a price on the under.
- Line movementLine movement is the change in a prop's posted number or price between when a sportsbook first posts it and now, and on Probetrics "moved" compares today's consensus number with the first one we stored.
- Alternate lineAn alternate line is a different number for the same prop than the main line, priced to match: an easier number pays less, a harder number pays more.
This page explains arithmetic and vocabulary. It does not recommend a bet, a side, an amount or a sportsbook, and the examples are illustrations. For information only, not betting advice. 21+ only. Gambling problem? Call or text 1-800-GAMBLER.