If you bet across different sites or exchanges, you’ll quickly notice that bookies display prices in different formats…
Some show 5/1, others 6.0, yet both represent the same underlying probability (16.7% in this case).
The challenge for most is understanding the differences so they can be compared effectively, ensuring you get the best deal.
So let’s break this down in layman’s terms…
What Fractional Odds Actually Mean (and Why They’re Confusing)
Fractional odds are the traditional British style of odds you see in horse racing and high-street bookmakers like William Hill. They show profit only, not your total return.
The idea is that the first part of the fractional odd stipulates the best potential. However, that then gets a bit confusing at uncommon fractions.
To make my point… 5/1 means “win £5 profit for every £1 staked”. Although 13/8 is a little confusing (it means win £1.63 for every £1 staked).
Further examples:
- A £10 bet at 5/1 returns £60 (£50 profit + £10 stake).
- Odds-on prices like 1/4 or 2/5 flip the logic – now you must stake more than you stand to win.
This is where fractional odds lose most people. Once you get into comparisons like 9/4 vs 13/5, the mental maths isn’t intuitive. You often need to pause, work out the ratio, and then decide which price is actually better. For some, this might be fine, but for serious bettors or anyone trading quickly, it becomes a bottleneck.
The best betting exchanges solve this problem with our next odds format…
They also introduced the accept all odds movement feature as a way of getting bets matched more easily amongst a moving market.
Decimal Odds: The Clearer, Faster Format
Decimal odds show the total return, stake included. If the odds are 6.0, a £10 bet returns £60 – no extra calculations, no remembering to add the stake at the end.
This is the reason Betfair and all major betting exchanges use decimal odds. When you’re comparing several prices across multiple selections or markets, decimals make it instantly obvious which selection offers the better return. A price of 3.75, for example, immediately reads as higher than 3.60. No conversion required.
For traders, matched bettors, and anyone analysing value, decimal odds remove friction. They also help with calculating break-even points: 2.0 simply means ‘double your money’ and anything above or below that becomes easy to interpret at a glance.
Fractional vs Decimal Odds: Simple Conversion Table…
| Fractional | Decimal | Meaning |
|---|---|---|
| 5/1 | 6.0 | £1 = £5 profit (£6 return) |
| 2/1 | 3.0 | £1 = £2 profit (£3 return) |
| 1/1 (Evens) | 2.0 | Break-even/double your money |
| 1/4 | 1.25 | £4 = £1 profit (£5 return) |
| 2/5 | 1.40 | £5 = £2 profit (£7 return) |
Here’s the conversion formula:
- Fractional → Decimal: (numerator/denominator) + 1
- Decimal → Fractional: decimal − 1, then convert to a fraction.
Which Odds Format Is Better?
Decimal Odds – Ideal for Traders, Value Bettors & Anyone Using Betfair
If your goal is speed, clarity, or accuracy, decimals are the better tool. They allow you to compare prices across markets without stopping to think, which is crucial when the market is moving. Advanced gamblers and traders especially prefer decimal odds because they mirror the way Betfair operates: the price you see is the exact multiplier on your stake.
This simplicity has real advantages. You can scan a market and know instantly which outcome offers the higher return. You can map implied probabilities more easily. And when you’re working with strategies like pre-race trading, football scalping, or matched betting, that clarity makes decision-making much faster and more confident.
For anyone serious about betting or Betfair trading – if you’re working with sharp bookmaker prices or navigating the exchange ladder – decimals tend to become second nature.
Fractional Odds – Better Suited to Traditional Bookies and Horse Racing
Fractional odds still have their place. If you’re standing in a betting shop on a Saturday afternoon or watching horse racing where fractions have always been the standard, the format feels familiar. UK bookmakers still present prices this way by default, and in those environments, the vast majority of punters get by without issue…
The downside is that fractions make comparisons slower. Working out whether 7/4 offers a better return than 6/5 requires a moment of calculation. It’s something you don’t have time for when the markets move fast. Fractions also make implied probability harder to see, which is one reason traders rarely use them (and bookies love them).
Still, for traditional players, fractional odds remain part of the culture.
Understanding Implied Probability (The Secret Behind “True Price”)
No matter which odds format you prefer or who you think the most valuable sports team is, what you’re really looking at is a bookmaker’s estimation of probability, plus their built-in margin. Decimal odds make this much easier to interpret because the formula is incredibly simple:
Implied probability = 1 / decimal odds × 100
A few common examples…
- 2.0 = 50% chance
- 4.0 = 25% chance
- 1.50 = 66.7% chance
Once you start thinking of odds in terms of probability, it becomes much easier to judge whether a price represents value or if the bookie has shaded the odds too far.
So Which Betting Odds Format Should You Use?
There’s nothing wrong with fractional odds if you’re placing the occasional bet in a shop or you’re used to the racing world’s language. But if you’re comparing multiple markets, trading on Betfair, analysing value, or simply want the easier format to understand, decimal odds are the smarter choice. If you’re just having a token flutter as you flick through the football fixures on the BBC it probably doesn’t matter so much…
Decimals reduce friction, speed up analysis, and make everything from pre-race trading to matched betting significantly clearer. For most modern gamblers, especially those aiming to improve their returns, switching to decimal odds isn’t just convenient, it’s a genuine performance advantage.
Related: Understanding the Maths Behind Betting Odds (Explained)