Discover the hidden margin (overround) in any bookmaker's odds. See exactly how much juice the bookie is taking and find the fairest odds for each outcome.
Choose the number of possible outcomes or use a preset. For football, use 3 (Home/Draw/Away). For tennis, use 2.
Input the bookmaker's decimal odds for each outcome. The calculator works in real-time as you type.
See the overround percentage, fair odds for each outcome, and a visual comparison. Lower margins mean better value for you.
Every bookmaker builds a margin into their odds. This means the implied probabilities of all outcomes add up to more than 100%. The excess is the bookmaker's profit margin, also known as the "overround" or "juice".
For example, in a fair coin toss both sides should be priced at 2.00 (50% each, totalling 100%). But a bookmaker might price both at 1.91, implying 52.4% each — a total of 104.8%. That 4.8% is the margin.
Margins vary significantly between bookmakers and markets. Top exchanges like Betfair often have margins below 2%, while traditional bookies range from 3% to 10% or more. Finding bookmakers with tighter margins saves you money over time, as the odds more closely reflect the true probabilities.
The "fair odds" shown by this calculator strip out the margin to show what the odds would be in a perfectly efficient market. Use these to compare and identify where you are getting genuine value.
See Also: Compare margins across bookmakers, then use our Arbitrage Finder to spot guaranteed profit opportunities. You can also convert odds to the same format first using our Odds Converter.
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