Sportsbooks around the world do not all display odds in the same way. Some use decimal odds, others use fractional odds, while many American sportsbooks use moneyline (American) odds.
Although the formats look different, they all describe the same thing—the probability of an outcome and the potential return if your bet wins.
Learning to convert between these formats allows you to compare prices accurately and avoid choosing a worse price simply because it is displayed differently.
Imagine two bookmakers offer the same football match:
At first glance, these odds appear unrelated.
However, after converting 6/4 into decimal odds, you get:
Both bookmakers are offering exactly the same price.
Without converting the odds into a common format, meaningful comparisons become difficult.
This is why experienced bettors almost always convert every price into decimal odds before analysing a market.
While these formulas may seem overwhelming at first, you rarely need to memorise all of them.
The easiest approach is to convert every odds format into decimal odds first.
Once everything is in decimal format, you can:
Because decimal odds include your original stake and are easy to calculate with, they have become the preferred format for analysts and professional bettors.
Try working through these examples until the conversions become automatic.
Fractional → Decimal → American
American → Decimal → Fractional
Decimal → Fractional → American
Practising these calculations regularly makes switching between bookmakers much faster.
If there is only one betting formula you remember, make it this one:
This formula converts any decimal price into the probability the bookmaker is assigning to an outcome.
For example:
Once every odds format has been converted into decimal odds, this single formula works every time.
Whether the original price was fractional, American, or decimal, the implied probability is always calculated in exactly the same way.
Different sportsbooks display odds in different formats, but they all represent the same underlying probability. The easiest way to compare prices is to convert every odd into decimal format first. From there, you can calculate returns, convert to other formats, and use the most important betting formula of all: Implied Probability = 1 ÷ Decimal Odds. Mastering this process will make comparing bookmakers and identifying value much easier.
