What Is Arbitrage Betting? Surebets Explained with Real Odds
Arbitrage betting means backing every possible outcome of one event at different bookmakers, at odds high enough that you win the same amount whatever happens. Such a combination is called a surebet or an arb. This guide shows the math with real prices, how often surebets appeared in 24,052 football matches, and what turns a calculated profit into a loss in practice.
Key takeaways
- A surebet exists when the sum of 1/odds over the best prices for every outcome falls below 1, and the profit is then 1 / sum − 1.
- In 24,052 matches of 2019–2023, the best 1X2 odds of six big bookmakers made a surebet in 1.43% of matches, with a median profit of 0.61%.
- Surebets are getting rarer: 2.2% of matches in 2019, 0.7% in 2023.
- The two prices 2.10 and 2.00 on over and under 2.5 goals return 2.44% on any score, but a 12% tax on stakes turns the same pair into a 9.85% loss.
- The biggest "surebets" in the data were bookmaker errors, which their terms let them void.
How does a surebet work?
Odds are the price of a chance: 1 / odds is the probability a bookmaker gives an outcome. At a single bookmaker these probabilities always add up to more than 1 across all outcomes of a market, and the excess is its margin. The prices 1.98 / 3.55 / 3.58 on a match result add up to 1.0661, a 6.61% margin. Where the margin comes from is explained in how bookmakers make money.
A surebet appears when you take the best price for each outcome, often from a different bookmaker each time, and the sum of 1/odds drops below 1. Then you can split your stake so every outcome pays the same, more than you put in. Two formulas do all the work:
- stake on an outcome = total stake × (1 / odds) / sum,
- profit = 1 / sum − 1.
A surebet does not need you to predict anything. That is what sets it apart from a value bet, which only pays over hundreds of bets: we compare the two in value betting vs arbitrage betting.
A surebet step by step
Bookmaker A pays 2.10 on over 2.5 goals, bookmaker B pays 2.00 on under 2.5 goals in the same match. The sum is 1 / 2.10 + 1 / 2.00 = 0.4762 + 0.5 = 0.9762, below 1. With 1,000 to stake:
| Bet | Odds | Stake | Returns if it wins |
|---|---|---|---|
| Over 2.5 goals at bookmaker A | 2.10 | 487.80 | 1,024.39 |
| Under 2.5 goals at bookmaker B | 2.00 | 512.20 | 1,024.39 |
| Total | 1,000.00 | profit 24.39 (+2.44%) |
The match ends either over or under 2.5 goals, so one of the two returns is certain. The profit, 1 / 0.9762 − 1 = 2.44%, does not depend on the score. Our surebet calculator does this split for two or three bets and shows every scenario.
Why do surebets appear?
Bookmakers price matches with their own models and react to team news, injuries and the flow of money at different speeds. When one raises the price on the home side and another has not yet cut the away price, both sides of the market together can cost less than 100% for a few minutes.
The other source is plain mistakes: swapped home and away prices or a misplaced decimal point. Such an "arb" looks the best of all, but the bookmaker's terms let it void the bet as an obvious error, a palp. We show how to spot them in palpable errors.
Surebets turn up most often:
- in less popular leagues and matches, where prices get less work,
- in side markets such as corners, cards or one team's goals, where every bookmaker runs its own model,
- in two-way markets such as tennis, basketball or totals, because two bets are enough,
- in the last hours before kick-off, when bookmakers update prices after team news at different speeds.
How often do surebets happen? Data from 24,052 matches
We checked the 1X2 odds of six big bookmakers from the football-data.co.uk database: 24,052 matches of 2019–2023 in 13 leagues of England, Germany, Spain, Italy, France, the Netherlands, Portugal, Belgium and Turkey. All six prices are recorded at one moment before each round. For every match we took the best price on home, draw and away.
| Best odds of six bookmakers | Matches | Share |
|---|---|---|
| Sum below 1: a surebet | 344 | 1.43% |
| Profit above 1% | 123 | 0.51% |
| Profit above 2% | 70 | 0.29% |
| Profit above 5% | 21 | 0.09% |
What the numbers say:
- A single bookmaker's margin in this sample ran from 3.2% to 6.8%. Even the best prices of six firms left at least 2.3% of margin in half the matches (median sum 1.023).
- A surebet turned up in about one match in 70, with a median profit of 0.61%, or 6.10 on 1,000.
- They are getting rarer: 2.2% of matches in 2019 (105 of 4,857), 0.7% in 2023 (34 of 4,918).
- Some were errors, not chances. In PSG – Metz in 2020 one bookmaker paid 29.00 on a Metz win while the other five paid 8.34 to 11.50.
This is an upper bound. A snapshot taken once before each round does not show how long a window stayed open, and in practice many surebets disappear within minutes.
Taxes and fees change the math
A surebet is only a surebet after every cost. A tax on stakes, such as the 12% Poland charges on every bet at licensed bookmakers, works as if every price were 12% lower: the condition becomes a sum below 0.88, not 1. The pair above then loses money:
| Bet | Odds | Odds after 12% tax | Stake | Returns if it wins |
|---|---|---|---|---|
| Over 2.5 goals at bookmaker A | 2.10 | 1.848 | 487.80 | 901.46 |
| Under 2.5 goals at bookmaker B | 2.00 | 1.76 | 512.20 | 901.46 |
| Total | 1,000.00 | loss 98.54 (−9.85%) |
In the six-bookmaker data a sum below 0.88 appeared twice in 24,052 matches, both times on obvious errors. Exchange commission works the same way on the winning side only, and currency conversion fees eat into every transfer. The calculator lets you set a stake tax and mark single bets as tax-free.
Types of surebets
- Two-way: two outcomes, such as over/under, both teams to score or a tennis match winner.
- Three-way: the classic home/draw/away with up to three bookmakers.
- Mixed: different markets that together cover every result, such as a home win at one bookmaker and double chance X2 at another.
The more bets in a surebet, the more room for mistakes in stakes and settlement rules. Advanced combinations such as middles and cross-market arbs are in advanced arbitrage strategies.
What can go wrong
Even a correctly calculated surebet can fail:
- the price moves before you place the second bet, and you are left with one unhedged bet,
- the bookmaker cuts your stake or accepts only part of it. Regular arbitrage is the most common reason for bookmaker limits,
- markets settle differently: a tennis retirement, overtime or a postponed match can mean different things at two bookmakers,
- an error gets voided, which turns a surebet into a plain bet,
- money is spread over several accounts, each tied up until the event is settled.
The full list, with an example of each and how to avoid it, is in arbitrage betting risks and common mistakes.
Is arbitrage betting legal?
Yes. Backing every outcome at different bookmakers breaks no law wherever betting itself is legal. Bet only with operators licensed where you live. Bookmakers, however, may limit or close the account of a player who wins through arbitrage, and many do.
Summary
A surebet is pure math: when the best prices for every outcome add up to less than 1 in probability terms, a fixed split of stakes wins whatever happens. Such chances exist but are rare and small: one match in 70 and a median 0.61% in our data, fewer every year. Taxes, commission and limits decide whether they pay at all. To get started, read how to start arbitrage betting, and to find them, see what matters in arbitrage betting software.
FAQ
What is a surebet?
A surebet, or arbitrage bet, is a set of bets on every outcome of an event at different bookmakers, at odds whose 1/odds add up to less than 1. The stakes are split so every outcome returns the same amount, more than the total staked.
How do you calculate a surebet?
Add 1 / odds for the best price on each outcome. If the sum is below 1, the profit is 1 / sum − 1, and the stake on each outcome is total stake × (1 / odds) / sum. With odds of 2.10 and 2.00 the sum is 0.9762 and the profit 2.44%.
How often do surebets appear?
In the 1X2 odds of six big bookmakers for 24,052 matches of 2019–2023, a surebet appeared in 1.43% of matches and a profit above 1% in 0.51%. The share fell from 2.2% in 2019 to 0.7% in 2023.
How much can you earn on a surebet?
Usually little per bet: the median profit in our data was 0.61% of the total stake. Larger margins of 5% and more were rare and often bookmaker errors that get voided.
Do taxes make surebets impossible?
A tax on stakes raises the bar. With a 12% tax on every bet, the sum of 1/odds must fall below 0.88, which happened twice in 24,052 matches, both times on obvious pricing errors.