Betting on sports is typically a losing proposition. You may win some bets but, on average, the house wins.
But there is an exception: promotional bets. If you are offered a free bet, it is possible to lock in a guaranteed profit by also placing a correctly-sized hedging bet that wins when your free bet loses. This is known as matched betting.
Not all matched betting combinations are made equal. Some can generate more guaranteed money than others. There are subscription services that will advise you on which options you should place your free bet on, which you should place the hedging bet on and the size of the hedge bet relative to the free bet.
These services tell you that the underlying math behind this is complex and so you should pay for an expensive monthly subscription so they can tell you which bets to place. The math really isn’t so complex actually but, even if you find it tricky, here is a simple alternative that shows how to earn the highest guaranteed profits from free bets.
Finding the Best Guaranteed Returns
I have provided two free Python programs (this one for if you are betting with US sportsbooks and this one for UK bookmakers). They scan the odds from various providers and show the best returns from placing a free bet with one book and the hedging bet with a different one.
Run them (details below) and they will tell you which are the best bet combinations.
The day I posted this (August 21, 2026), the best option available from US odds listed at FanDuel, DraftKings and BetMGM was an MMA bout between Reinier de Ridder and Roman Dolidze. Betting a $1 free bet on de Ridder at +340 and $2.68 on Dolidze at -375 produces a guaranteed profit of 71.5c.
The UK code also picks out a similar relatively mismatched MMA bout. Typically, the best return comes from placing the free bet on an underdog (but not an incredible longshot) and then placing a larger bet on the corresponding favorite.
As I described in this paper, the algebra on this is all driven by the fact that the free bet is typically a stake-not-returned bet, so you only get the profit back from the bet if you win. I show how if the bookmaker applies a fixed margin to each bet, then there is a “sweet spot” that maximizes the guaranteed profit, typically placing the free bet on an option that has about a 20% chance of winning. For this kind of bet, with typical bookmaker margins/hold percentage, you can get about 70% of the free bet stake as a guaranteed profit.
How to Run the Code
- Install Python and VS Code. Here is a simple video explaining how to do this. You will have to install some basic packages like pandas (you just type pip install pandas at the command prompt in VS Code.)
- Sign up for a free starter membership with https://the-odds-api.com/ You can run this code several times a month before hitting your free tier credit limit of 500 credits (the trade-off is that the more sports you scan, the more credits it will cost).
- Place your API key in a text file called .env in the same directory you are running the code from.
- Specify the output directory that you want the spreadsheet to go to.
- Run the code and look at the answers in the spreadsheet that it creates.
Once you have the code you can use Odds-API’s site to adjust the list of bookmakers, sports and betting market
Some FAQs
Don’t I need to use a betting exchange or prediction market to place “Lay” bets?
Nope. UK discussions of matched betting seem to always invoke the need to use Betfair for your hedging bet. This seems to be based on the assumption that you can only bet on soccer or horses. But two-outcome events are available every day: American sports like baseball and basketball and other sports like tennis and MMA have only two outcomes. And the latter two sports are particularly good at generating combinations that are right in the “sweet spot” that my paper shows maximizes guaranteed profits.
Can you guarantee I will make the predicted profit?
Nope. I have checked the data from The Odds API against real-time quotes and they seem to be accurate but the odds may change between when you run your code and actually place your bets.
Will I get banned by bookmakers?
If you place your free bet with one bookmaker and your hedge with another, each bookmaker can only see the bet you placed with them. That said, regular bettors don’t place bets for $30.17, so using the precise size for the hedging bet that is suggested by the code may get you profiled as someone engaging in arbitrage. And bookmakers hate people doing this. They consider it “promotional abuse”.
Will it get you thrown out before you place all the free bets you can get from starting accounts with a bunch of bookmakers? Maybe, maybe not. Don’t email me to complain. One option is to round the hedging bet to something more natural looking, thus exposing yourself to a tiny bit of risk. Alternatively, you can amend the code to pick out the best options available if you restrict the free and hedging bets to “normal looking” amounts. Any decent AI can do that for you.
Is this really risk free?
No. You might do it wrong and put the free and hedging bets on the same options. Or you may not realize the odds have moved in between placing your first or second bet.
Use this code at your own risk. It is free research code, not a commercial matched-betting service. Check every price and bet yourself before placing it.
But, done correctly, it is pretty close to risk free. Indeed, it is sufficiently safe that it is regularly discussed on Mumsnet.
How much money can I make?
Not as much as used to be possible. Promotions are generally not as generous as they used to be and typically, once your promotional bonuses from opening a new account are used up, you won’t get much more from them.
And this is time consuming. For all I know, it may not be more lucrative on an hourly rate basis than delivering pizza. Here is a fun article from Vice on the matched betting experience from a few years ago.
Are you encouraging people to bet?
Nope. My book Fine Margins describes all the different ways that people lose money on sports betting. It cannot be interpreted as in any way encouraging people to bet. But if bookmakers are going to offer people the opportunity to make some guaranteed money, then it is perfectly reasonable that some people will choose to take advantage of it.
A mistake that perhaps some people can make is to start imagining they can win at real betting just because they earned some profit from matched betting. You almost certainly can’t.
How do I know Odds-API won’t shut down their free tier?
You don’t.
I couldn’t get the code to run. Will you help me?
No! How much spare time do you think I have?