Sports Betting Odds Calculator
Convert American Odds to Decimal Odds or Fractional Odds with our free sports betting odds calculator. Also calculate implied probability and calculate sports betting payout.
Enter positive (+150) or negative (-150)
(Optional) Enter your bet amount
Odds Conversion Results
by EyeOnTheBet.com
Enter odds above to see conversion results
How to use: Select your odds format and enter the odds as shown on your sportsbook. Results will calculate automatically. Add your stake (optional) to see potential payout amounts.
Our sports betting odds calculator is the most fundamental tool for sports bettors and sports gambling. Whether you're line shopping across multiple sportsbooks that use different betting odds formats, trying to understand what +200 or -110 odds mean, or calculating the implied probability to identify value bets and positive expected value (+EV) opportunities, this free odds converter handles it all instantly.
Enter betting odds in any format (American moneyline odds +/-, Decimal, or Fractional) and see instant conversions to all other odds formats, plus implied probability percentage and exact payout for any stake amount. Essential for beginners learning how to read betting odds and experienced bettors comparing value across bookmakers and betting sites.
How to Read Betting Odds:
All Formats Explained
Different sports betting sites and betting markets around the world display betting odds in different formats. American sportsbooks and online sports betting sites primarily use American odds (moneyline format with +/-), European bookmakers favor decimal odds, and British betting sites traditionally use fractional odds. Understanding how to calculate betting odds in all three formats is essential for line shopping, comparing true value across different sportsbooks, and finding the best sports betting odds for your wagers.
American Odds
Use + and - signs to show
underdogs and favorites
-150 means bet $150 to win $100 profit
+150 means bet $100 to win $150 profit
Decimal Odds
Multiply your stake by the decimal
to get your total return
1.5 odds on $100 = $150 total return
2.50 odds on $100 = $250 total return
Fractional Odds
First number = profit
Second number = stake
1/3 means win $1 for every $3 wagered
3/1 means win $3 for every $1 wagered
Quick Sports Betting Odds Conversion Chart
| American | Decimal | Fractional | Implied Probability |
|---|---|---|---|
| -180 | 1.56 | 14/25 | 64.29% |
| -150 | 1.67 | 67/100 | 60% |
| -110 | 1.91 | 91/100 | 52.38% |
| +100 | 2.00 | 1/1 | 50% |
| +150 | 2.50 | 3/2 | 40% |
| +200 | 3.00 | 2/1 | 33.33% |
| +300 | 4.00 | 3/1 | 25% |
Frequently Asked Questions
An odds calculator is a free tool that converts betting odds between American (+/-), decimal, and fractional formats while calculating implied probability and potential payouts. It's essential for comparing odds across different sportsbooks and understanding the true value of any bet.
For positive American odds (+150), divide by 100 and add 1: (150/100) + 1 = 2.50 decimal. For negative American odds (-150), divide 100 by the absolute value and add 1: (100/150) + 1 = 1.67 decimal. Our calculator does this instantly for any odds.
Implied probability is the likelihood of an outcome as suggested by the betting odds, expressed as a percentage. It represents the bookmaker's assessment of the event happening plus their profit margin. Calculate it by dividing 1 by decimal odds and multiplying by 100. For example, 2.50 odds = (1/2.50) * 100 = 40% implied probability.
Decimal odds are easiest for calculations and are used worldwide. American odds are standard at US sportsbooks. Fractional odds are traditional in UK betting. The "best" format depends on what you're familiar with and which sportsbooks you use. This calculator lets you work in any format and see all conversions.
Fractional odds show profit relative to stake using a fraction. 3/1 (three-to-one) means you win $3 profit for every $1 wagered. The first number is profit, the second is stake. 5/2 means bet $100 to win $250 profit. 1/2 means bet $100 to win $50 profit (favorite). Even odds are expressed as 1/1 or "Evens".
-110 is the standard odds for point spreads and totals at most US sportsbooks. It means you must bet $110 to win $100 profit. This represents the sportsbook's juice (vigorish) - their built-in commission. The implied probability of -110 is 52.4%, meaning the sportsbook takes about 2.4% on each side.
Compare the implied probability from odds to your own assessment of the true probability. If you believe an outcome has a 50% chance but the odds imply 40%, that's a value bet. Use our calculator to see implied probability instantly, then compare to your handicapping analysis to identify positive expected value (+EV) opportunities.
This calculator converts single bet odds between formats. For parlay calculations (combining multiple bets), use our dedicated Parlay Calculator. However, you can use this tool to convert parlay odds from one format to another or calculate the implied probability of your parlay odds.