The essentials
Fractional and decimal odds express the same relationship in different formats. Fractional odds emphasise potential profit relative to the stake. Decimal odds show the total potential return, including the original stake.
At 6/4, a £4 stake could produce £6 profit and a £10 total return. The equivalent decimal price is 2.50.
Reading fractional odds
The first number is the potential profit and the second is the stake used for the ratio. At 5/2, every £2 staked could produce £5 profit. Stakes do not have to match the denominator because the return scales proportionally.
A £10 stake at 5/2 gives potential profit of £25. If the selection wins, the total potential return is £35 after adding the original £10 stake.
Reading decimal odds
Multiply the stake by the decimal price to calculate the total potential return. Subtract the stake if you want the potential profit alone.
A £10 stake at 3.50 produces a potential total return of £35 and potential profit of £25. This is the same return as 5/2.
Converting between the formats
| Conversion | Formula | Example |
|---|---|---|
| Fractional to decimal | (numerator ÷ denominator) + 1 | 6/4 becomes 2.50 |
| Decimal to fractional | decimal odds - 1, then express as a fraction | 3.50 becomes 2.50/1 or 5/2 |
| Decimal to probability | 1 ÷ decimal odds × 100 | 2.50 becomes 40% |
The complete guide to how betting odds work connects prices, returns, probability and margin in one place.
Profit, return and other common mistakes
- Comparing a fractional profit figure with a decimal return figure.
- Forgetting that the decimal return includes the original stake.
- Reading odds-on prices such as 4/6 as if they were 6/4.
- Rounding a converted price too aggressively before calculating a return.
- Assuming equal-looking formats represent different chances.
Use the information responsibly
Better calculations can improve your understanding, but they cannot make an uncertain outcome certain. If you choose to bet, set affordable money and time limits before you start. Never use money needed for bills, borrow to bet or increase a stake to recover a loss.
If gambling is causing worry or affecting your finances, relationships, sleep or wellbeing, the National Gambling Helpline offers free support around the clock on 0808 8020 133.
BetOwl responsible gambling information →Sources and review
BetOwl checked the calculations independently and reviewed the regulatory and safer gambling context against the sources below.
- Gambling Commission: rules, game descriptions and likelihood of winning
- GamCare: safer gambling and National Gambling Helpline