Arbitration Betting (Surebets): Theory, Risks, and Practical Limits

On the surface, Arbitrage betting is a dream scenario. Place two or more wagers on every position in a market. The prices are at such a level that you make a bit of money with whichever turns out to be the winning wager. That’s the theory and it holds up beautifully in a spreadsheet. But this is not the case in practical application. There’s maximum bet limits, potential voids placed by the bookies, time constraints to get all your bets on, terms and conditions and that’s what we’ll be covering here. We’ll walk through how it works in theory, where it goes wrong in practice, and if it can still be used to good effect on today’s betting markets.

What is arbitration betting (surebets)?

What is arbitration betting? In short, this is “surebetting”, where you bet on all outcomes in a market across multiple sportsbooks such that the total implied probabilities are less than 100%. If you keep betting the right amounts you guarantee to make a profit: Surebets Simple example: only 2 outcomes for a tennis match, one bookie offering good odds for Player 1, another bookie offering good odds for Player 2, but the “total probability” offered by those two bookies is less than 100%, then you have found a surebet. You bet in such a way that the return (not profit) is guaranteed to be the same for both outcomes. That’s how surebets work. Sounds easy? It isn’t in practice, because odds change, bet slips get suspended, your account gets limited, terms are different for each bookie etc. Surebets are not “risk-free” in a chaotic reality. You need agility, discipline and to know what you’re doing. For the basics of implied probability, read this: Implied Probability (Investopedia).

Simple case: a tennis match has two outcomes. If one bookmaker has high odds on Player A and another has high odds on Player B, the “sum of implied probabilities” can be less than 100%. Then there is a surebet. You split your stakes so your payout is the same on both sides.

Odds can be converted into “implied probability.” (Implied probability = 1 / odds for decimal odds.) If you sum the implied probabilities for all outcomes and they total less than 100, then you’ve found space for a surebet.

How surebets work: the math in plain words

Who will win the match: W1 – first team to win in regular time without overtime, W2 – second team to win in regular time without overtime, X – draw at the end of regular time without overtime; Who will be the winner of the game, including overtime: Y1 – first team to win the match with overtime, either by a golden goal or in extra time; Y2 – game won by the second team...

Two-outcome example

Implied probability:

Book A: Team A at 2.10
Book B: Team B at 2.05

Sum = 96.40%. This is less than 100%, therefore there is a surebet.

Team A: 1 / 2.10 = 0.4762 (47.62%)
Team B: 1 / 2.05 = 0.4878 (48.78%)

Sum = 96.40%. This is under 100%, so there is a surebet.

“FreeShare” is actually free to use. Unlike arbitrary mandatory fees, a voluntary “Thank You” fee simply wouldn’t work

Stake on Team A = 100 × (2.05 / (2.10 + 2.05)) = 49.40
Stake on Team B = 100 × (2.10 / (2.10 + 2.05)) = 50.60

anything after this point will not be particularly relevant so you can stop reading this article now. In terms of the

If Team A wins: return = 49.40 × 2.10 = 103.74 → profit ≈ 3.74
If Team B wins: return = 50.60 × 2.05 = 103.73 → profit ≈ 3.73

this article here for more on this]. To reiterate though, this idea works fine without the need for a voluntary “thank you”

Three-way markets

Soccer 1X2 has three outcomes: Home, Draw, Away. You need the sum of the three implied probabilities to be under 100% for a surebet. It is harder to find and often smaller in edge.

Back–lay surebet (with an exchange)

Here you “back” a result at a bookmaker and “lay” the same result on a betting exchange (you bet against it). Exchanges charge commission on winnings. That changes the numbers.

In Soccer 1X2 there are three events: Home, Draw, Away. In this case, you have to get the sum of all implied probabilities to less than100%. It is much more difficult to track this down, and usually will come with a much smaller edge.

Back at bookmaker: odds 3.20, stake 100
Lay at exchange: odds 3.10, commission 2%

Here you “back” a result at a bookmaker and “lay” the same result on a betting exchange (you bet against it). Exchanges charge commission on winnings. That changes the numbers.

Example (2% exchange commission): Added to Queue

So Lay stake = 100 × 3.20 / (3.10 − 0.02) = 103.90

To balance the profit whichever account wins, you need a lay stake such that

If result wins: bookmaker profit = 100 × (3.20 − 1) = 220; exchange loss (liability) = (3.10 − 1) × 103.90 = 218.19 → net ≈ +1.81
If result loses: bookmaker loses 100; exchange win = 103.90 × (1 − 0.02) = 101.82 → net ≈ +1.82

In our example, this gives:

Types of surebets you will see

Two-way markets (tennis, basketball moneyline). Pros: simple, fast. Cons: small edge, limits hit fast.
Three-way markets (soccer 1X2). Pros: many games. Cons: rule traps, smaller edges, more steps.
Back–lay (bookmaker vs exchange). Pros: clear hedging. Cons: commission, liquidity, liability size.
Cross-market quirks (rule differences, e.g., tennis retirements). Pros: sometimes big edges. Cons: high risk if rules do not match.

Where surebets come from

Timing gaps: some sites move odds slower than others.
Different margins: one book takes lower margin to win users.
Promos and boosts: boosted odds can create a surebet window.
Data feed errors: rare but real; sites fix fast.
Rule differences: how a sport settles can shift real value.

Windows are short. Good arbs can vanish in seconds. Tools can help, but discipline and checks matter more.

Practical limits: why scaling is hard

This is the most important part. Math is easy. Operations are not. Here is what limits growth:

Stake limits and “gubbing”: many sportsbooks limit sharp users fast. You may be asked for “trader review,” or you get tiny max bets. Some will close your account. See the UK regulator for general rules on operators: UK Gambling Commission.
Liquidity: small leagues and player props can look good, but you cannot get enough money down. Exchanges can be thin near kickoff. You will face slippage.
Fees and commission: exchange commission and payment fees cut margins. A 2% fee can remove most of a 2% surebet.
KYC and holds: sites must follow AML/KYC rules. That means ID checks, proof of funds, and holds. Learn what KYC is from the UK’s FCA: Know Your Customer.
Bet delays: you click, the site delays, odds change, and only one leg lands. Then you scramble to hedge. You may lock a loss.
Time cost: you must scan, check rules, place, and log each bet. Your real hourly return is much lower than the raw edge suggests.
Capital spread: you need money across many sites and e-wallets. Funds get stuck during KYC or weekends. Float management is work.
Diminishing returns: bigger stakes draw faster limits. Your yield falls as size grows.

Arbitrage opportunities can dry up in seconds. Seconds! You need to be fast and accurate ... if you don't use specialist software, it's unlikely you'll be able to locate opportunities before they disappear ... but one can get addicted to speeding, which can (and often will) lead to mistakes, so always double and triple check everything:

Risks you must manage

This is the most crucial point. The math is the easy part. The operations are not. This is where the growth constraints are:

Voids and palpable errors

Palpable error: a clear odds mistake. Many books can void such bets. The UK ADR service IBAS shares guidance and cases: IBAS.
Event void or rule change: weather, late scratches, or other issues can cancel one leg but not the other.

Rule mismatches

Tennis retirements: some sites pay on the player who moves to next round, some void, some need one set to be done. Read rules for each site. See an example of sport rules at Betfair: Tennis Rules (Betfair).
Baseball pitchers: action vs listed pitchers can settle in different ways.
Soccer same-game markets: some combos are “related,” so books void or reject.

Execution risks

Bet acceptance lag: the first leg is placed, the second leg moves. You must pre-plan a hedge path. Sometimes the best move is to take a small, known loss.
Human error: wrong stake, wrong market, wrong team. Use checklists.
Rounding and currency: different currencies and stake rounding can change cents that eat your edge.

Account risks

Limits and closures: “gubbing” after a few weeks is common. Keep accounts clean and do not abuse promos.
Compliance holds: AML checks can freeze funds for a while. Keep clean records of deposits and withdrawals.

Legal, tax, and duty risks

Laws differ by country and state. In the UK, see the regulator: UKGC. In the US, check your state on the AGA map: State Gaming Map.
Taxes differ by country. In the US, see IRS Topic 419 on gambling income: IRS Topic 419. In the UK, tax is different and may not apply to casual bettors, but rules can change; see general income tax info at HMRC: HMRC Income Tax. Always ask a local tax pro.

Risk control checklist

Use smaller stakes at first. Aim for edges over 1% net after fees.
Read and save the rules for each sport and each site.
Before you click, decide the plan if odds move.
Prefer markets with clear, simple settlement (match winner, moneyline).
Keep an audit trail: screenshots, bet IDs, timestamps.
Use fast and stable payment rails. Avoid slow bank wires if you need speed.
Track every arb in a sheet. Note outcome, fees, and any issues.

Tools, workflow, and skills

You do not need fancy tools. You need speed, checks, and logs.

Odds screeners / alert tools help find arbs fast. Choose one that covers your books.
Surebet calculator: use any trusted calculator to split stakes. Cross-check by hand.
Bookmaker limits tracker: note which sites cut limits and how fast.
Workflow: verify rules → place bets (fast leg first) → confirm both legs → log the arb → reconcile later.
IP and device hygiene: do not jump IPs in odd ways; sites may flag this.
Fast funding: e-wallets or instant bank rails help move float.

Focus on clear process. That saves more money than any tool.

Choosing bookmakers and reliable review sources

You do not need fancy tools. You need speed, checks, and logs.

Known payout speed and low withdrawal friction
Stake limits and how they change
Clear sport rules and track record on voids
Good mobile app speed and clean bet slip UX
Payment fees and exchange commission (if any)
Local license and responsible gambling tools

Put process first. That will save more money than any tool.

If you need to escalate a dispute in the UK, learn how ADR works at IBAS: Independent Betting Adjudication Service.

Bankroll, legal, and tax basics

Bankroll size: start small. Many people use 1–5% of bankroll per arb, then split between legs.
Float: keep extra funds so you can hedge if the second leg changes.
Fees: note exchange commission, currency FX fees, and withdrawal costs.
Laws: only bet in places where it is legal and licensed. Check your regulator (e.g., UKGC in the UK, or your state body in the US via the AGA map).
Taxes: keep records for every bet. For the US, read IRS Topic 419: Gambling Income and Losses. Ask a local tax pro for your case.

Is arbitrage betting still worth it in 2025?

It can be worth it at small scale if you are careful and patient. You can learn a lot about markets and risk. At big stakes, it is much harder. Limits, holds, and fees will push your return down. Some people move on to other edges, like value betting, middling, or trading on exchanges. Start small, track your net after all costs, and be honest about your time.

FAQ

Is arbitrage betting legal?

At lower levels it’s still okay and if you’re diligent enough then you may persevere. You will likely learn a lot and you will likely face situations you’ve never come across before. This is always a good thing. The returns, as mentioned, will test your good days. Once you reach bigger stakes, though. It’ll get much tougher. Limits and holds will grind your profit margin down and the fees will also eat into it. Some punters will open themselves up for the less grindier ways of profiting such as value betting, middling or even trading or looking for better returns from the betting exchanges. Always start small, always keep account of both your inputs and outputs (after fees) and calculate if what you’re doing will be worthwhile to warrant you spending your spare time doing it.

How much money do I need to start?

You can start with a few hundred. It is easier with more float so you can place and hedge fast across sites. Start small and learn the steps first.

What is a realistic monthly return?

It depends on time, books, and limits. Many small arbers see 0.5–2% net per completed arb after costs. Your month will vary with season and account health.

What if odds move after I place the first leg?

Have a plan. Often you take a small known loss and move on. Do not let one bad hedge become a big hole. A clear plan beats hope.

How do bookmakers detect arbers?

Patterns: always taking boosted outliers, fast pre-match hits, low-margin markets, and stake sizing that matches calculators. Limits can come fast. Mix markets, keep stakes modest, and do not chase promos too hard.

Are betting exchanges safer for arbing?

Exchanges do not limit in the same way, but they have commission and can have low liquidity. You also hold liability on lay bets. Know your numbers and size.

Can I do this without software?

Yes, but it is slow. A simple odds feed helps a lot. Even with a tool, always check rules and numbers by hand before you bet.

What records should I keep for taxes?

Keep a log of every bet: date, event, market, stakes, odds, payout, fees, and exchange commission. Save screenshots and bet IDs. For the US, see the IRS guide: IRS Topic 419.

Sources and further reading

UK Gambling Commission — licensing and player info
IBAS — dispute resolution (UK ADR)
Betfair Exchange: Commission
Smarkets: Rules and Regulations
American Gaming Association: State Gaming Map
BeGambleAware — responsible gambling (UK)
National Council on Problem Gambling (US)
GamCare — help and advice
FCA: Know Your Customer
Investopedia: Implied Probability

Responsible gambling and compliance notes

Only bet if you are of legal age where you live.
Gambling has risk. Do not bet money you cannot afford to lose.
Use limits and self-exclusion tools if needed. See BeGambleAware (UK) or NCPG (US) for help.
This article is for education. It is not legal, tax, or financial advice.

About the author and review process

This guide was edited by a sports betting analyst and checked against public rules from major exchanges and regulators listed above. We update this page to reflect new rules, fees, and common risks. If you spot an error, please contact the editor with sources.

Last updated: 2025-12-17

Quick recap

Surebets work when the sum of implied chances is under 100%.
Small edges are common; big ones are rare and risky.
Main limits: account cuts, fees, liquidity, KYC holds, and time cost.
Main risks: voids, rule mismatches, bet delays, and human error.
Use a clear process, keep logs, and start small.
Before you add new books, read trusted reviews like Gambling Sites, and check rules and payout speed.