Before decimal odds became the global standard, fractional odds were the traditional way bookmakers displayed prices. They are still commonly used in the United Kingdom and Ireland, particularly in horse racing and some football betting markets.
Unlike decimal odds, which show your total return, fractional odds show how much profit you make relative to your stake.
Fractional odds are written as two numbers separated by a slash, for example:
The two numbers have different meanings:
For example, odds of 5/2 mean you earn £5 in profit for every £2 you stake, plus your original stake is returned if the bet wins.
The formula for calculating profit is:
Example:
Profit:
Your original stake is then added back to calculate the total return.
In this example:
Unlike decimal odds, fractional odds are not always easy to compare at a glance.
For example, which price is better?
Without performing a calculation, many people cannot immediately tell which offers the higher return.
Historically, bookmakers often displayed prices such as 11/4, 13/8, or 85/40, making quick comparisons more difficult for bettors.
Today, decimal odds have largely replaced fractional odds in most countries because they are much simpler to understand and compare.
You can easily convert fractional odds into decimal odds using the following formula:
The +1 is important because decimal odds include your original stake, while fractional odds only show your profit.
Example:
So, fractional odds of 5/2 are exactly the same as decimal odds of 3.50.
Another example:
This is why "even money" (1/1) is equivalent to decimal odds of 2.00.
Although many modern bookmakers allow you to choose your preferred odds format, understanding fractional odds is still useful because they remain common in British betting markets and older betting literature.
Being able to convert between fractional and decimal odds also makes it much easier to compare prices across different bookmakers and betting exchanges.
Fractional odds express profit relative to your stake, while decimal odds show your total return. Profit is calculated by multiplying your stake by the fraction, and converting to decimal odds simply requires dividing the numerator by the denominator and adding one. Understanding both formats allows you to compare prices confidently, regardless of how a bookmaker displays its odds.
