Picture a normal Wednesday at Wolverhampton. You have found a horse you like at 4/1 with the bookmakers. A quick look at the exchange shows 5.4 on the same horse. That is decimal odds, which include your stake back, so it works out at about 4.4/1, a slightly bigger price. Does it matter which one you use?
Often the answer is yes, a little. The question this guide answers is where to place a bet when you want the best chance of making it pay, and what that choice can and cannot do for you.
Should you bet with the bookies or on Betfair?
For many racing bets the Betfair Exchange offers a slightly better price, because you are betting against other people rather than a bookmaker who has built a margin into the prices. That edge is small, and it only becomes profit if the selection itself is value. The exchange does not turn a losing method into a winning one. At best it makes a value method cost you less to run. I have not measured bookmaker prices against exchange prices for this guide, so treat the price gap as a general tendency rather than a measured figure.
Where the bookmaker’s margin hides
Bookmaker prices have a margin baked into them, and it is hidden inside the odds. Add up the implied chances of all the runners in a race from a bookmaker’s prices and the total comes to more than 100 per cent. That overshoot is called the over-round, or market percentage, and it is the bookmaker’s built-in cut. A full explanation is in our guide to how market percentage is calculated. You pay it on each bet, win or lose, though it is only visible when you add the prices up.
The exchange works differently. You are matched against another person who wants the opposite side, so the book on a busy race tends to sit closer to 100 per cent. There is no bookmaker margin to feed, only a thin layer of commission on your net winnings. The same horse is therefore often available at a slightly bigger price on the exchange. A slightly bigger price on bet after bet, over years, can add up. How much depends on the race, the time of day and how busy the market is.
What the exchange changes, and what it does not
It is tempting to conclude the exchange is simply where profit lives. Not so fast. A better price on a bad bet is still a bad bet. If your selections have no edge, moving them from the bookies to Betfair may slow your losses, but it will not stop them. The exchange suits an approach that already finds value, and it does little for one that does not.
There is also commission to be honest about. Betfair takes a small percentage of your net winnings on each market, so the headline price is not quite the price you keep. In our own analysis we judge results at Betfair Starting Price (the price the exchange settles at, often shortened to BSP) after 2% commission, because that is closer to what lands in your account. Compare like for like, and do not assume the raw exchange odds are free money.
And the exchange offers something a bookmaker does not: you can lay a horse, betting on it to lose rather than to win. That opens up whole approaches, such as opposing a vulnerable favourite or trading a price as it moves. Whether you ever use it is up to you, but it is worth knowing it is there. Our guide to backing versus laying goes into more detail.
Favourites: the same bet at two different prices
The simplest way to see this is to take the most popular bet in racing, the favourite, and ask what happens at a fair price. Here are the verified figures for the Betfair SP favourite in GB and Ireland races from 1 July 2013 to 14 October 2026, at Betfair SP, one point level stakes, 2% commission, with fallers and pulled-up horses counted as losers:
- Races: 167,257.
- Won: 34.4% of the time.
- A/E: 1.00. A/E compares actual winners with the winners the prices implied, so 1.00 means results matched the odds.
- Return: -1.4%.
- Longest losing run: 28.
These figures describe that stretch of racing and will not repeat exactly, but they paint a clear enough picture. At exchange prices the favourite was close to fairly priced, and the small loss is consistent with commission. That suggests blind favourite-backing was not a winning plan at Betfair SP. It would likely have been worse at bookmaker prices, where the bookmaker’s margin applies, though I have not tested that here.
In an earlier analysis, the favourite’s win rate moved around by class, from 29.6% in Class 2 to 37.2% in Class 4, and by type of racing, from 32.5% on Flat turf to 37.3% over hurdles. Win rates moved around. What the earlier work did not show was a clear pocket where backing favourites blind was value.
The point for the bookies versus Betfair question is simple. On the exchange, a fairly priced favourite costs you the thin slice of commission. At a bookmaker, the same horse has to overcome a book that sits above 100 per cent, so the identical bet is likely to cost more. Neither fact is a reason to back favourites for the sake of it.
A reason many serious bettors end up on the exchange
There is a reason beyond price. If you start winning with a bookmaker, your account may not stay open for long. Bookmakers can restrict or close accounts that show a profit, often cutting stakes to small amounts. People who bet for profit talk about this a lot, and it is a common frustration. You can be right about a horse and still find the bookie will only let you have a few pounds on it. Our guide on how to stop bookies restricting your account covers what is within your control.
The exchange makes its money from commission whether you win or lose, so it has less reason to turn away a winner. If your ambition is to turn a genuine edge into larger stakes over time, that is a practical argument for the exchange. One thing to keep in mind is that the exchange does not restrict you like a bookmaker, but how much you can get matched still depends on how busy the market is, and quieter races may only take small stakes. It is not a guarantee, and it does not matter at all unless you have an edge to begin with.
How to decide where to place each bet
None of this means you cannot use a bookmaker. For a casual bet, offers such as best odds guaranteed, each-way concessions, the occasional price boost and the convenience of a quick small stake can all make a bookmaker the sensible choice. If you are having a small bet on a Saturday handicap for fun, the pennies the exchange might save are not worth the bother.
But if you are betting to make money, a sensible order of operations looks like this. Find a selection you believe is value, meaning a horse whose real chance is bigger than its price implies. Then take the biggest price you can actually get on, which for a larger stake will often be the exchange. To check whether your selections are beating the market, use the A/E ratio, which compares how often an angle wins with how often its Betfair Starting Price said it should. An A/E above 1.00 over a large sample would suggest you are beating the market. Below 1.00, no venue can fix the method. Samples under about 1,000 bets are suggestive only.
So the bookies versus Betfair question is best asked second. Get the selection and the value right first, and then use whichever venue gives the better price for that bet.
To start putting that into practice, open today’s race cards, find a runner you think is value, and compare the bookmaker price with the exchange price before you decide where to have the bet.
