Arbitrage betting means backing every outcome of an event at different bookmakers, at prices that add up to less than 100%. Whatever happens, one bet wins enough to cover the others. Arbs are small, rare and short lived, and bookmakers restrict accounts that bet them.
Why arbs happen
Every bookmaker sets its own prices. Most of the time they're close, and each one has a margin built in, so backing every outcome at one bookmaker loses money. Now and then one bookmaker is slow to move a price, or two disagree, and the best prices across the market leave a gap.
How to check for an arb
Turn each price into an implied chance: 1 divided by the decimal odds. Add them up. Over 100% is a normal market. Under 100% is an arb.
| Home | Draw | Away | Book total | |
|---|---|---|---|---|
| One bookmaker | 2.40 | 3.40 | 3.10 | 103.3% |
| Best prices | 2.50 | 3.60 | 3.40 | 97.2% |
The best prices add up to under 100%, so there's an arb worth about 2.9% of the stake.
Working out the stakes
Stake each outcome in proportion to its implied chance. With £100 in total:
| Outcome | Odds | Stake | Return if it wins | Profit |
|---|---|---|---|---|
| Home | 2.50 | £41.16 | £102.89 | £2.89 |
| Draw | 3.60 | £28.58 | £102.89 | £2.89 |
| Away | 3.40 | £30.26 | £102.89 | £2.89 |
Round the stakes to whole pounds and the profit varies by a few pence between outcomes. The arbitrage calculator shows exactly how much.
Check your prices and split your stakes.Arbitrage calculator →What goes wrong
- The price moves. You place the first bet, and before the second goes on the price has shortened. Now you have an ordinary bet or a smaller arb.
- A bet is voided. Bookmakers can cancel bets at obvious mistake prices, called palpable errors. Big arbs are often exactly that.
- Rules differ. One bookmaker settles a tennis match on a retirement, another voids it. A dead heat or extra time can do the same.
- Accounts get restricted. Bookmakers spot arb patterns quickly and cut stakes, often to pennies.
Each arb only makes a few percent. One voided bet can cost more than many arbs make.
Finding arbs
Arbs don't last long, so checking prices by hand rarely finds them in time. Most people who arb use software that scans many bookmakers and shows the gaps, along with the stakes for each side.
Arb and value betting tools we rate
Arbs with a betting exchange
If a bookmaker's price is higher than the exchange lay price, you can back at one and lay at the other. That's the same set up as matched betting, without an offer. For example, £100 backed at 2.2 and laid at 2.1 with 2% commission makes £3.65 either way.
Work out a back and lay arb.Matched betting calculator →Questions people ask
Is arbitrage betting legal in the UK?
Yes. It's not against the law, but bookmakers can restrict or close accounts that do it.
How much can you make from arbitrage betting?
A few percent of what you stake on each arb, before mistakes and voided bets. Restrictions usually limit how long you can keep doing it.
Is arbitrage the same as matched betting?
They use the same idea of covering every outcome. Matched betting uses free bets to make the profit. Arbitrage relies on prices that disagree.