Free odds calculator
Implied Probability Calculator for Betting Odds
By DeepChamp research team · Updated · Methods and limitations
Short answer
The implied probability of a price is the share of the time an outcome must happen for a bet at those odds to break even. Enter American odds for one side, or both sides of a market, to see the break-even probability and the margin.
Implied probability calculator
American odds, for example -110 or +150.
Add it to see the margin in the market.
| Implied probability at -110 | 52.38%break-even win rate |
|---|---|
| Decimal odds | 1.909 |
| Profit per 100 risked | $90.91 |
| Implied probability at -110 | 52.38%other side |
| Both sides added together | 104.76%anything over 100% is margin |
| Margin | 4.55%share of the market |
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Researching a real market? Use the numbers in the app.
Download on the App StoreHow to use it
- 1Enter the American odds for the side you are researching.
- 2Optionally enter the other side of the market to see how much margin the operator has added.
- 3Compare the break-even probability with your own estimate of the outcome, and be honest about how uncertain that estimate is.
- 4Remember that the same price at a different operator has a different break-even point.
How the math works
Every betting price is a claim about probability once you remove the payout. A price of +200 asks you to believe the outcome happens more than one time in three, because a win pays two units for each one risked. A price of -200 asks for more than two in three.
When both sides of a market are shown, the two implied probabilities add up to more than 100 percent. The excess is the overround, and it is the operator margin you pay on every bet in that market. Researching a bet means comparing a probability you believe with a break-even probability that is slightly worse than fair.
- Positive American odds
- probability = 100 / (odds + 100)
- Negative American odds
- probability = |odds| / (|odds| + 100)
- Margin of a two-way market
- overround = p1 + p2, margin = (overround - 1) / overround
Common questions
How do you calculate implied probability from American odds?
For positive odds use 100 divided by the odds plus 100, so +150 is 100 / 250 or 40 percent. For negative odds use the absolute value divided by itself plus 100, so -150 is 150 / 250 or 60 percent.
What is the difference between implied and break-even probability?
For a straight bet they are the same number: the win frequency at which you neither gain nor lose over time at that price. The word implied emphasizes that it comes from the odds rather than from any real-world forecast.
Why do the two sides of a market add up to more than 100 percent?
The operator builds a margin into both prices so that, if wagers balance, it earns a return whichever side wins. That excess over 100 percent is also called the vig or the overround.
This is educational research content. Examples use hypothetical numbers and are not live odds, picks, or claims about performance.
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