Prop Bet Calculator: Payouts, Fair Odds & Expected Value for NFL, NBA & MLB

A prop bet calculator is one of the most useful tools in your sports betting toolkit. Instead of guessing what a prop bet will pay out or whether the odds represent good value, you can plug in the numbers and see the math instantly. This calculator works across major US sports including NFL, NBA, and MLB player props, and it is completely free and mobile-friendly.

This guide will show you how to use the prop bet calculator to work out payouts, understand implied probability, remove vig to find fair odds, and calculate expected value for your bets. You will also see worked examples for NFL, NBA, and MLB props, learn about same game parlays and correlation, and understand how advanced tools like no-vig calculators and Kelly Criterion can fit into your strategy.

By the end, you should be able to use the calculator confidently to make better decisions and understand your real risk. This is for information and education only. Betting always involves risk, and you should never wager more than you can afford to lose. Sports betting is for adults 21+ only in legal US states.

How to Use the Prop Bet Calculator

Using a prop bet calculator is straightforward once you understand the inputs and outputs. The goal is to turn raw odds and stake into actionable information: what you might win, what the market is implying, and whether you have an edge.

Step 1 – Enter Your Prop Bet Details

Start by entering the basic details of your prop bet:

• Sport: Select NFL, NBA, MLB, or other supported sports
• Market type: Choose the prop market, such as player yards, points, assists, strikeouts, touchdowns
• Odds format: American (e.g. -110, +150), Decimal (e.g. 1.91, 2.50), or Fractional (e.g. 10/11, 3/2)
• Stake size: Enter how much you plan to bet in dollars

Most US bettors use American odds, which is the default format for most sportsbooks. If you see odds like -110 or +200, select American format. If you see odds like 2.00 or 1.50, select Decimal.

Step 2 – See Payout & Implied Probability

Once you enter your details, the calculator will instantly show you:

• Total payout: Your stake plus profit if the bet wins
• Profit: Your net win after deducting the stake
• Implied probability: The probability implied by the odds, expressed as a percentage

Implied probability is one of the most important numbers in sports betting. It tells you what the market thinks the chance of your bet winning is. For example, odds of -110 imply about 52.4 percent chance of winning. Odds of +150 imply about 40 percent.

Example (for illustration only, not betting advice):

• Market: NFL anytime touchdown scorer
• Odds: +150
• Stake: $20
• Output:
  • Total payout: $50
  • Profit: $30
  • Implied probability: 40 percent

If you think the true chance of this player scoring is higher than 40 percent, you may have a positive expected value bet.

Step 3 – Remove the Vig for Fair Odds (Optional)

Vig, also called juice or hold, is the sportsbook's built-in edge. On any two-sided market, the combined implied probabilities of both sides will add up to more than 100 percent. That extra percentage is the vig.

If you enter both sides of a market into the calculator, it can estimate the bookmaker margin and output no-vig fair odds and fair probability. This helps you understand what the market might look like without the house edge.

For example, if a prop is priced at Over -110 and Under -110, the combined implied probability is about 104.8 percent. The calculator can strip out that 4.8 percent vig and show you the fair odds for each side.

Step 4 – Calculate Expected Value (EV)

Expected value is the average outcome you can expect from a bet over the long run. To calculate EV, you need two inputs:

• The odds offered by the sportsbook
• Your own projected win probability

If your projected win probability is higher than the implied probability, the bet has positive expected value. If it is lower, the bet has negative expected value.

The calculator will display:

• EV per $1 bet: How much you expect to win or lose per dollar wagered over many bets
• Total EV: Your expected value based on your stake size

Important: EV is an average over many bets, not a guarantee for any single bet. Even positive EV bets can lose, and even negative EV bets can win in the short term.

What Is a Prop Bet? (Beginner Foundation)

Definition & Common Types

A prop bet, short for proposition bet, is a wager on a specific event or performance within a game that does not directly decide the winner. Instead of betting on which team wins or the final score, you are betting on individual stats, milestones, or game events.

Common types of prop bets include:

Player props:

• Passing yards, rushing yards, receptions, touchdowns (NFL)
• Points, rebounds, assists, threes made (NBA)
• Strikeouts, hits, home runs, total bases (MLB)

Team props:

• Total team points, first team to score, team with most yards

Game props:

• Will the game go to overtime, winning margin, longest touchdown

Player props are the most popular type and the focus of most prop bet calculators.

Why Prop Bets Are Different From Spreads & Moneylines

Prop bets differ from traditional markets in a few key ways:

• Independence: Your prop can win even if your team loses the game
• Volatility: Props can be more unpredictable than spreads or totals
• Higher vig: Sportsbooks often charge more juice on props than on main markets
• Less efficiency: Prop markets may be less sharply priced than spreads, creating opportunity for value

Because prop bets are more volatile and carry higher vig, bankroll management is even more important. Never bet more than a small percentage of your total bankroll on any single prop, and always be prepared for variance.

Understanding Your Results – Payouts, Probability & EV

Payout & Profit

The payout is the total amount you receive if your bet wins, including your original stake. The profit is your net win after deducting the stake.

Example (for illustration only, not betting advice):

• Stake: $50
• Odds: +120
• Payout: $110 (stake of $50 + profit of $60)
• Profit: $60

On favorite odds like -150, you risk more to win less. On underdog odds like +200, you risk less to win more. Always check the payout and profit before placing a bet to make sure the risk/reward matches your expectations.

Implied Probability

Implied probability converts odds into a percentage chance. It shows you what the sportsbook thinks the likelihood of your bet winning is, including the vig.

American Odds	Implied Probability
-110	52.4%
+100	50.0%
+150	40.0%
+200	33.3%
+300	25.0%

Use implied probability to compare the market's estimate to your own projection. If you think a player has a 50 percent chance of going over a yardage line, but the market implies only 40 percent, you may have found value.

Fair Odds & No-Vig Probability

No-vig odds are the fair odds after removing the sportsbook's margin. By entering both sides of a market, the calculator can estimate what the odds would be in a theoretical zero-vig market.

This is useful for:

• Comparing markets between different sportsbooks
• Identifying where the vig is highest
• Understanding the true fair value of a prop

For a deeper dive into no-vig concepts and EV calculations, see our Prop Betting Strategy Guide.

Expected Value (EV) and Long-Term Profitability

Expected value is the single most important concept in sports betting. It tells you whether a bet is profitable in the long run, even if individual outcomes are unpredictable.

EV formula (simplified):

EV = (Win probability × Profit) - (Loss probability × Stake)

If EV is positive, the bet is theoretically profitable over many repetitions. If EV is negative, the bet is a long-term loser.

Example (for illustration only, not betting advice):

• Your projection: 50 percent chance of winning
• Market odds: +150 (40 percent implied)
• Stake: $100
• Profit if you win: $150
• EV = (0.50 × $150) - (0.50 × $100) = $75 - $50 = +$25

This bet has positive EV of $25, meaning you expect to win an average of $25 per bet if you repeat it many times. Individual bets can still lose, but over the long run, positive EV bets should be profitable.

Prop Bet Examples for NFL, NBA and MLB

NFL Prop Bet Example

Market: Anytime touchdown scorer

• Player: Travis Kelce
• Odds: +140
• Stake: $25
• Implied probability: 41.7 percent
• Your projection: 50 percent
• Payout if win: $60
• Profit: $35
• EV: Positive (you project higher than the market)

NFL touchdown props are popular during primetime games and playoffs. Key factors to consider include red-zone usage, matchup against the opponent's defense, and game script.

NBA Prop Bet Example

Market: Player points + assists (PRA)

• Player: Luka Doncic
• Line: Over 42.5 PRA
• Odds: -110
• Stake: $50
• Implied probability: 52.4 percent
• Your projection: 58 percent
• Payout if win: $95.45
• Profit: $45.45
• EV: Positive

NBA props often involve combination stats like points + rebounds + assists. Consider usage rate, pace, opponent defensive ranking, and rest/injury status.

MLB Prop Bet Example

Market: Pitcher strikeouts

• Player: Gerrit Cole
• Line: Over 7.5 strikeouts
• Odds: -120
• Stake: $30
• Implied probability: 54.5 percent
• Your projection: 60 percent
• Payout if win: $55
• Profit: $25
• EV: Positive

MLB pitcher props depend heavily on matchup, ballpark, weather, and recent performance. Strikeout props tend to be more stable than hit or home run props.

For more detailed player prop strategies across all major sports, see our Player Prop Betting Strategy Guide and Player Props Betting Guide.

Same Game Parlays, Multi-Prop Bets & Correlation

Same game parlays, or SGPs, let you combine multiple props from the same game into one ticket. All legs must win for the parlay to pay out. SGPs are exciting and can offer big payouts, but they are also complex and often carry extra vig.

What Same Game Parlays (SGPs) Are

A same game parlay combines two or more selections from the same game. For example, you might bet:

• Patrick Mahomes over 275.5 passing yards
• Travis Kelce anytime touchdown
• Kansas City Chiefs to win
• Total points over 47.5

If all four legs hit, the parlay pays out at combined odds. If any leg loses, the entire bet loses.

Why Correlation Matters (e.g. QB Yards and WR Yards)

Correlation refers to how the outcomes of different legs are related. In same game parlays, correlation can be positive, negative, or neutral.

Positive correlation:

• QB passing yards and WR receiving yards (same team)
• Team to win and player on that team to score a touchdown

Negative correlation:

• Team to win big and opponent player to go over yards (game script conflict)

Sportsbooks adjust SGP odds to account for correlation. When legs are positively correlated, the combined payout is lower than if you bet them separately. This is often called the "correlation tax."

How EV Calculations Become More Complex

Calculating EV for same game parlays is more complex than for single bets because you need to account for correlation, joint probabilities, and vig on each leg. Most bettors do not have the tools or models to calculate SGP EV accurately, which is why sharp bettors often avoid them.

If you do bet SGPs:

• Keep leg counts low (2-3 legs maximum)
• Avoid stacking highly correlated legs
• Compare SGP odds to manually building separate parlays to check for value

For a full guide to same game parlay strategy and correlation, see our Prop Betting Strategy Guide.

Advanced Tools – No-Vig, Arbitrage & Kelly Criterion

No-Vig Calculator

A no-vig calculator removes the sportsbook's margin from the odds to show you the fair probability and fair odds. This helps you identify which markets have the highest vig and which books are offering the best value.

To use a no-vig calculator, enter both sides of a two-way market (e.g. over and under). The tool will output the estimated vig percentage and the fair odds for each side.

Arbitrage and Middling (High-Risk, Advanced)

Arbitrage betting involves placing bets on both sides of a market at different sportsbooks to guarantee a profit regardless of the outcome. This is possible when odds differences create a mathematical edge.

Middling involves betting both sides of a market at different lines, aiming to win both bets if the result lands in the middle.

Both strategies are advanced, carry operational risks, and can lead to account restrictions. They are not recommended for casual bettors.

Kelly Criterion & Bankroll Management

The Kelly Criterion is a mathematical formula for determining optimal bet size based on your edge and bankroll. It helps you maximize long-term growth while managing risk.

Many bettors use fractional Kelly, such as quarter Kelly or half Kelly, to reduce variance and protect against estimation errors.

For more on bankroll management and Kelly Criterion, see our Prop Betting Strategy Guide.

Responsible Gambling & Legal Considerations

Prop betting is legal for adults 21+ in regulated US states where online sports betting is licensed. Always use legal, licensed sportsbooks in your state and never bet with offshore or unlicensed operators.

Remember:

• No guarantee of profit, even with positive EV
• Variance and losing streaks are normal
• Set deposit and loss limits before you start
• Never bet more than you can afford to lose

If you feel that your betting is no longer fun or is affecting your relationships, work, or finances, reach out for help. Call 1-800-GAMBLER or visit the Problem Gambling Help page for resources and support.

Frequently Asked Questions (FAQ)

How does this prop bet calculator work?

This calculator takes your prop bet details, such as odds, stake, and market type, and calculates your potential payout, profit, implied probability, fair odds, and expected value. It works for NFL, NBA, MLB, and other major sports.

Can I use this calculator for live bets?

Yes, you can use this calculator for live bets by entering the current odds and your stake. However, keep in mind that live odds change quickly, so always confirm the odds on your sportsbook before placing a bet.

Is using a prop bet calculator legal in my state?

Using a calculator to help you understand your bets is completely legal. However, sports betting itself is only legal in states where it is licensed and regulated. Check your state's laws and only bet with licensed sportsbooks.

What's the difference between implied probability and fair probability?

Implied probability includes the sportsbook's vig and represents what the market is pricing. Fair probability is the estimated true probability after removing the vig. Fair probability is always lower than implied probability on favorites and higher on underdogs.

Does a positive EV guarantee I'll win money?

No. Positive EV means you expect to win money over the long run if you repeat the bet many times. Individual bets can still lose, and variance can cause long losing streaks even with positive EV.

Can this calculator handle Same Game Parlays?

This calculator can approximate payout and probability for independent legs, but same game parlays involve correlation and more complex math. For SGP-specific tools, check with your sportsbook or use dedicated SGP calculators.

Do you use my data to place bets for me?

No. This calculator is for information and education only. It does not place bets, access your accounts, or store your personal data. All calculations happen in your browser.