Decimal odds: total return and profit
For a standard winning cash bet, total return equals stake multiplied by decimal odds. Profit equals that return minus the stake. This distinction is also explained in Betfair’s decimal-odds guide. Fees, tax, bonus conditions and exceptional settlement rules are outside this simple calculation.
Our example uses a stake of 24 units and decimal odds of 2.75. The illustrative total return is 24 × 2.75 = 66 units. Subtract the original 24 units and the profit is 42. Calling the full 66 profit would count the original stake as new money.
If that cash bet loses, the stake is lost. Neither the 66-unit return nor the 42-unit profit is money already earned. Keep this distinction when reading a calculator result or a bet slip.
Convert fractional and American odds
Fractional odds of a/b convert to decimal odds of 1 + a/b. In our example, 7/4 becomes 1 + 7/4 = 2.75. With a 24-unit stake, the fractional profit calculation is 24 × 7/4 = 42, matching the decimal calculation.
Positive American odds A convert to 1 + A/100. Thus +175 also becomes 2.75. Negative American odds −A, where A is the positive magnitude, convert to 1 + 100/A. At −200 the decimal price is 1.50: an 80-unit winning cash stake would return 120 in total, including 40 in profit.
- 7/4, +175 and 2.75 express the same price before any deductions.
- 1/2, −200 and 1.50 express another equivalent price.
- A minus sign in American odds does not mean a negative return.
Calculate implied probability from odds
Convert decimal odds D into an implied percentage with 100/D. At 2.75, that gives approximately 36.36%. Betfair’s odds explainer describes the conversion; our calculator uses the same arithmetic for standard prices.
The result describes the price, not a measured chance of this particular event. It is also the break-even win rate in a simplified repeated-bet calculation at constant odds, with no fees or other adjustments. A displayed percentage alone cannot tell you whether the underlying assessment is accurate.
Bookmaker margin: add the implied probabilities
For our fictional two-outcome market, suppose both outcomes have decimal odds of 1.90 and exactly one can win. Each price implies 100/1.90 = 52.63%. Adding the unrounded values gives approximately 105.26%, or 5.26 percentage points above 100%.
That excess is the overround in this simplified complete market. It is not a prediction that every player will lose precisely 5.26% of their stake, and it is not a forecast of the operator’s realised profit. Stakes, outcomes and changing prices matter. A market with a possible draw needs the draw price included before this addition makes sense.
Try the odds calculator
In the Canada Bet Guide odds calculator, enter decimal 2.75 and stake 24; then switch to fractional 7/4 or American +175. Each should show the same illustrative return. Try −200 with stake 80 to check the second example.
The tool handles a single standard price. It does not price accumulators, each-way deductions, exchanges after commission, free-bet stake rules or cash-out offers. Those need the exact product terms. No conversion removes the possibility of losing the cash stake.
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