Fractional odds show potential winning profit as a ratio to stake. Multiply the stake by the numerator divided by the denominator to calculate profit, then add the stake for total return. At 3/2, a fictional ten-unit stake produces 15 units of profit on a full win.
Read the ratio
In fractional odds a/b, the numerator a describes profit for b units of stake. The fraction describes profit, not total return. This distinction is the main difference between reading fractional and decimal prices.
For a fictional ten-unit stake at 3/2, the profit is 10 × 3 ÷ 2 = 15 units. Adding the original stake gives a 25-unit total return. These calculations exclude fees and assume normal winning settlement.
Work through familiar fractions
| Fraction | Decimal equivalent | Profit on 10 units | Total return |
|---|---|---|---|
| 1/2 | 1.50 | 5 units | 15 units |
| 1/1 | 2.00 | 10 units | 20 units |
| 3/2 | 2.50 | 15 units | 25 units |
| 2/1 | 3.00 | 20 units | 30 units |
The decimal conversion is 1 + a/b. Equivalent fractions describe the same ratio: 6/4 and 3/2 both equal 1.5 profit units per stake unit. A different-looking fraction is not necessarily a different price.
Convert to implied probability
The formula is b ÷ (a + b). At 3/2, this is 2 ÷ 5 = 0.40, or 40%. The result is a price-implied percentage rather than a confirmed prediction.
A market can include margin or other costs. The implied figure should not be presented as evidence that a selection has exactly that probability of winning. Define whether you are describing a price or making an independent forecast.
Avoid common errors
Do not multiply the stake by both numbers. Divide the numerator by the denominator first, or perform the equivalent stake × numerator ÷ denominator operation. Do not call 15 units the total return in the ten-unit 3/2 example: that is the profit.
Check that the denominator is positive and nonzero. A malformed fraction is not a usable price. Round calculated displays deliberately rather than silently changing the input.
Read settlement separately
Fractional notation does not specify whether overtime counts, what happens in a tie or how a void is handled. Those are market and operator rules. The examples concern a straightforward winning selection only.
The broader odds guide compares all three formats. The market guide explains the event condition behind the selection. Together they help distinguish the payout calculation from the sporting uncertainty.
Sources and method
This guide was prepared with AI assistance. Fictional examples are original educational demonstrations; they are not live sporting data or betting recommendations. Calculations use the assumptions stated in the text. No independent expert review is claimed.
- Odds and implied probability reference ↗ · checked 2026-10-06
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Read a related guide for more context. Analysis and odds education do not guarantee an outcome or return.
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