Sports Betting Odds Calculator

Convert odds formats, calculate implied probability, expected value, and parlay payouts.

Enter Odds

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Parlay Calculator (Optional)

Quick Facts

Break-Even
-110 odds = 52.4%
Standard juice/vig
Even Money
+100 = 2.00 = 1/1
50% implied probability
Typical Vig
4.5% - 10%
Sportsbook edge
Kelly Criterion
(bp - q) / b
Optimal bet sizing

Odds Conversion & Analysis

Calculated
American Odds
+150
US format
Decimal Odds
2.50
European format
Fractional Odds
3/2
UK format
Implied Probability
40%
Bookmaker's estimate
Potential Payout
$250
Including stake
Expected Value
+$12.50
Per $100 bet

Parlay Analysis

Value Assessment

Understanding Sports Betting Odds

Sports betting odds represent the probability of an outcome and determine your potential payout. Different regions use different formats - American odds dominate in the US, decimal odds in Europe and Australia, and fractional odds in the UK. Understanding how to convert between formats and calculate implied probability is essential for informed betting.

Odds Formats Explained

American Odds: Shown as positive (+) or negative (-) numbers. Positive odds show profit on a $100 bet (+150 means $150 profit). Negative odds show how much to bet to win $100 (-150 means bet $150 to win $100).

Decimal Odds: Represent total payout including stake. Odds of 2.50 mean a $100 bet returns $250 total ($150 profit + $100 stake). Simply multiply stake by decimal odds for total return.

Fractional Odds: Show profit relative to stake. Odds of 3/2 mean $3 profit for every $2 bet. A $100 bet at 3/2 returns $250 ($150 profit + $100 stake).

Implied Probability = 1 / Decimal Odds x 100%
For American odds: Positive: 100 / (odds + 100) | Negative: |odds| / (|odds| + 100)

Expected Value (EV)

Expected value measures the average profit or loss per bet over time. Positive EV (+EV) bets are profitable long-term; negative EV (-EV) bets lose money over time. Professional bettors seek +EV opportunities consistently.

EV Formula: (Win Probability x Potential Profit) - (Loss Probability x Stake)

A bet with 10% edge means you'd expect to profit $10 per $100 wagered over many bets. Our calculator compares your estimated probability against the bookmaker's implied probability to identify value.

Parlay Betting

A parlay combines multiple bets into one, with all legs needing to win for a payout. While payouts are higher, the combined probability decreases multiplicatively. Use our parlay calculator to see combined odds and true implied probability before placing multi-leg bets.

Responsible Gambling

Sports betting should be entertainment, not income. Only bet what you can afford to lose, set strict bankroll limits, and never chase losses. If gambling causes financial or personal problems, seek help from organizations like the National Council on Problem Gambling (1-800-522-4700).