Calculator
Convert American Odds to a Percentage
Enter one moneyline price. Add the opponent price when you want margin and no-vig analysis.
Use your browser print dialog to save the calculated result as a PDF.
Examples
Example Data Table
| Moneyline odds | Implied probability | Meaning |
|---|---|---|
| -200 | 66.67% | Favorite price. Risk 200 units to profit 100 units. |
| -110 | 52.38% | Common near-even price with a small market margin. |
| +100 | 50.00% | Even-money price. Profit equals the stake. |
| +150 | 40.00% | Underdog price. A 100-unit stake can profit 150 units. |
Calculation method
Formula Used
Negative moneyline odds
For -150, the calculation is 150 ÷ (150 + 100) × 100 = 60.00%.
Positive moneyline odds
For +150, the calculation is 100 ÷ (150 + 100) × 100 = 40.00%.
Optional no-vig calculation
When both opposing prices are entered, their implied probabilities show the market margin. Dividing each probability by the total produces a proportional no-vig comparison.
Instructions
How to Use This Calculator
- Enter the American moneyline shown for your selected outcome.
- Enter your planned stake to estimate profit and total return.
- Select a display precision from zero to six decimal places.
- Optionally enter the opposing moneyline to examine vig and no-vig probability.
- Select Calculate Percentage. The result appears directly below the header.
- Download a CSV report or use Print or Save PDF for a shareable summary.
Guide
Understanding Moneyline Implied Probability
Why moneyline percentages help
Moneyline odds show how a sportsbook prices a possible outcome. Negative odds identify the favorite. Positive odds identify the underdog. The number describes a payout relationship. A negative price shows the amount risked to earn one hundred units. A positive price shows profit from risking one hundred units. These formats can seem unfamiliar because their scale changes. Implied probability puts formats onto one percentage scale. That percentage estimates the win rate needed to break even before fees or limits.
Reading favorites and underdogs
A moneyline of minus one hundred fifty means risking one hundred fifty units to earn one hundred units. Its implied probability is sixty percent. A moneyline of plus one hundred fifty means earning one hundred fifty units from a one hundred unit stake. Its implied probability is forty percent. Those prices are opposites. Real markets include extra margin. Two opposing implied probabilities can add to more than one hundred percent. That excess is called vig, margin, or overround. It reflects built-in market pricing.
Using the advanced fields
This calculator converts either moneyline direction into implied probability. Enter a negative favorite price or a positive underdog price. Add a stake to view possible profit and total return. The stake does not change probability. It only changes payout figures. Select decimal places. An optional opposing moneyline activates market analysis. The results show both probabilities, their combined probability, the implied margin, and a no-vig estimate. No-vig probability removes margin proportionally. It is a comparison tool, not a true chance.
Comparing available prices
Use implied probability to compare prices across several sportsbooks. A lower percentage for the outcome indicates a better price. Confirm the bets are identical. Compare the event, market type, settlement rules, and timing. Lines can move after injuries, news, or large wagers. Recalculate after changes. Plus one hundred twenty implies about forty-five point forty-five percent. Plus one hundred thirty implies about forty-three point forty-eight percent. The second price needs a lower win rate to break even. Small differences matter over bets.
Limits of probability
Probability does not predict a result by itself. It translates a price into a usable benchmark. Your own estimate matters. A wager may have value only when your estimated chance exceeds the market implied probability. For example, an outcome priced at forty percent may be attractive when research suggests forty-five percent. Estimation is difficult. Keep records and assess decisions over samples. Avoid treating one result as proof that a method works. Bankroll rules matter. Use stakes that protect you during losing stretches.
Important practical details
Moneyline conversions assume American odds. They do not account for taxes, promotional terms, exchange commissions, cash-out offers, or correlated selections. Parlays require separate calculations because risk differs. Markets with pushes, draws, dead heats, or special rules need extra review. Always read the sportsbook rules. Use this calculator as a transparent pricing aid. It can help compare numbers, identify margin, and understand break-even expectations. The result supports informed decisions, but it never removes uncertainty from any market.
Common questions
Frequently Asked Questions
What does implied probability mean?
It is the break-even win percentage suggested by the listed odds. It translates a betting price into a percentage, so favorites and underdogs are easier to compare.
Why do negative odds have higher percentages?
Negative moneylines usually describe favorites. They require a larger risk to make one hundred units of profit, so they convert to a higher implied probability.
Why do positive odds have lower percentages?
Positive moneylines usually describe underdogs. They show how much profit a one hundred unit stake can earn, which generally reflects a lower implied probability.
Does the stake amount change the percentage?
No. The implied probability depends only on the moneyline. The stake amount changes the potential profit and total return shown by the calculator.
What is market margin or overround?
It is the amount by which both sides’ implied probabilities exceed one hundred percent. It represents pricing margin built into the displayed market.
What is no-vig probability?
It proportionally removes the visible market margin after both opposing odds are entered. It is useful for comparison, but it is not a guaranteed prediction.
Can I enter +100 odds?
Yes. A +100 moneyline is even money. It has a 50.00% implied probability, and a winning stake earns equal profit.
Can I enter -100 odds?
Yes. A -100 moneyline is also even money. It converts to a 50.00% implied probability and equal risk-to-profit terms.
Why might two opposing percentages exceed 100%?
Sportsbooks often include a margin. When both sides are converted, that margin causes their combined implied probabilities to exceed one hundred percent.
Does this calculator predict game outcomes?
No. It converts prices into mathematical probabilities. Outcomes remain uncertain, and personal research, market changes, and event rules can matter.
How should I use the calculated result?
Use results to compare prices before placing any wager.