Betting Odds Calculator
Convert between American, decimal, and fractional odds. Calculate payouts, implied probability, vig, and no-vig fair odds — instantly.
How to Use the Betting Odds Calculator
This free betting odds calculator converts between the three major odds formats used worldwide: American odds (used in the US, e.g. -110, +150), decimal odds (used in Europe and Australia, e.g. 1.91, 2.50), and fractional odds (used in the UK, e.g. 5/1, 10/11).
Enter odds in any format to instantly see the equivalent in all three formats, plus the implied probability and payout for your stake. Switch to the No-Vig Calculator tab to see the true fair odds after removing the sportsbook's margin (vig/juice).
For developers building betting tools, SharpAPI provides all of these calculations programmatically via API — real-time odds from 20+ sportsbooks with built-in +EV detection, no-vig fair odds, and arbitrage alerts. Get a free API key to start building.
Odds Formats Explained
American Odds
Shown as positive (+150) or negative (-110) numbers. Negative odds show how much to bet to win $100. Positive odds show how much you win on a $100 bet.
-110: Bet $110 to win $100
+150: Bet $100 to win $150
-200: Bet $200 to win $100
Decimal Odds
Multiply by your stake to get total payout (including stake). Always greater than 1.0. Popular in Europe, Australia, and Canada.
1.91: $100 × 1.91 = $191 payout
2.50: $100 × 2.50 = $250 payout
1.50: $100 × 1.50 = $150 payout
Fractional Odds
Shown as a fraction (5/1, 10/11). The numerator is profit per unit of stake (denominator). Common in UK horse racing and football.
5/1: Win $5 for every $1 bet
10/11: Win $10 for every $11 bet
1/2: Win $1 for every $2 bet
Frequently Asked Questions
How do American odds work?
American odds show how much you win on a $100 bet (positive) or how much you need to bet to win $100 (negative). -110 means bet $110 to win $100. +150 means bet $100 to win $150.
How do I convert American odds to decimal?
For positive odds: (odds/100) + 1. For negative odds: (100/|odds|) + 1. Example: -110 = (100/110) + 1 = 1.909. +150 = (150/100) + 1 = 2.500.
What is implied probability?
Implied probability is the odds converted to a percentage showing the likelihood of an outcome. -110 odds imply a 52.4% chance. It includes the sportsbook's vig (edge), so the true probability is lower.
What is vig (juice)?
Vig is the sportsbook's built-in edge. On a standard -110/-110 line, the implied probabilities add to 104.8% — the extra 4.8% is the vig. Lower vig means better value for bettors.
What are no-vig fair odds?
No-vig odds remove the sportsbook's margin to show true probabilities. SharpAPI calculates these using Pinnacle's sharp lines as the reference — giving you the real fair price for any market.
How do I find +EV bets?
A +EV (positive expected value) bet has odds better than the true probability. Compare sportsbook odds against no-vig fair odds — if the sportsbook is paying more than fair value, it's +EV. SharpAPI calculates this automatically via the API.
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