Explainer · 6 min read

Is arbitrage betting gambling? What the law says and what the maths says

Arbitrage betting (sure betting) covers every outcome of a match, so the result no longer decides whether you win. Does that mean it is not gambling? The answer depends on whether you ask a lawyer or a mathematician. This explainer gives both views, the risks that remain, and why the rules on age and responsible gambling apply either way.

Updated 22 October 2026

Contents

The legal view
The maths view
The risks that remain
Why the RG rules still apply
Summary
FAQ
Sources

The legal view: a sure bet is ordinary betting

For the law it makes no difference whether you place one bet or two bets that cover each other. Each leg of a sure bet is a normal sports bet with a bookmaker, at odds the bookmaker offered. How sports betting is classified depends on the country.

Austria

The federal Gambling Act (Glücksspielgesetz, GSpG) defines a game of chance as a game "in which the result depends exclusively or predominantly on chance" (§ 1(1) GSpG). According to the settled case law of the Supreme Court (OGH), sports betting does not fall under this definition, because the outcome of a sporting event also depends on assessable factors such as the strength of the teams. The OGH has confirmed this for over/under bets as well.

That does not mean sports betting is unregulated. The nine federal states regulate it in their own laws, for example the Vienna Betting Act (Wiener Wettengesetz), with licences for bookmakers, betting rules and youth protection. Many online bookmakers serving Austrian customers hold a licence from another EU country, often Malta, in addition or instead.

Germany

The Interstate Treaty on Gambling 2021 (GlüStV) expressly counts sports betting as gambling (§ 3(1)). Online sports betting needs a German licence, and the Joint Gambling Authority of the German states (GGL) keeps the official list of licensed operators.

Slovakia

The Slovak Gambling Act (Act No. 30/2019 Coll.) counts betting games, including sports betting, as gambling. Online, only operators with a Slovak licence may offer bets. The regulator ÚRHH publishes a list of legal operators and a list of prohibited offers.

United Kingdom

The Gambling Act 2005 defines gambling as gaming, betting or participating in a lottery (section 3). Sports betting is therefore gambling, regulated by the Gambling Commission.

In every one of these countries, sure betting itself is not prohibited. Comparing odds is legal, also with software. What matters is the bookmaker's licence for your country and its terms. More in tax and legality, Austria's betting tax and Slovakia's betting tax.

The maths view: chance is covered

With an ordinary bet, the result of the match decides whether you win or lose. With a sure bet you bet on every outcome, at different bookmakers, so that each side pays out roughly the same.

Worked example: over/under 2.5 goals

Bookmaker A offers "over 2.5 goals" at 2.05, bookmaker B "under 2.5 goals" at 2.02. The test: 1/2.05 + 1/2.02 = 0.4878 + 0.4950 = 0.9828. If the sum is below 1, it is a sure bet, here with a margin of about 1.75%.

With €200 in total you stake €99.27 at A and €100.73 at B. If three or more goals are scored, A pays €203.50; if fewer, B pays €203.47. Either way about €3.50 is left.

Assumptions: decimal odds, both bets accepted in full at the shown odds and not voided, no betting fee, amounts rounded. Real results can differ and can be negative.

Whether three goals are scored or not does not matter for the result. In that sense a sure bet is not a bet on the outcome, but the use of a price difference between two providers. How such differences arise is explained in arbitrage in finance and in betting; the formula is in the arbitrage calculator.

What remains: the residual risks

The calculation above only holds if everything goes to plan. In practice there are risks no calculator removes:

Odds change. The second price drops before you can place it, and the combination no longer covers every outcome with a profit.
Voided bet. One bookmaker cancels a leg, for example because of an obvious price error. The other leg stays open and can lose.
Different settlement rules. For tennis retirements or overtime, bookmakers sometimes settle differently. Then one outcome is not covered.
Partial acceptance and maximum payouts. The bookmaker accepts only part of the stake or caps the payout.
Your own mistakes. Wrong market, wrong stake, wrong match.
Limits and account closures. Bookmakers restrict winning accounts. That is not a loss in itself, but it limits how long sure betting works.
Payout problems. Especially with bookmakers not licensed in your country, you have little protection in a dispute.
Betting fee passed on. If a bookmaker passes Austria's 5% betting fee on to you, the margin is usually gone.

In detail, with what you can do about each: arbitrage betting risks. Whether sure bets are worth it under these conditions is discussed in does arbitrage betting work?

Why the responsible gambling rules still apply

Even if the maths covers chance, sure betting happens on betting accounts. You see individual wins and losses on every account, you have money sitting with bookmakers, and the advertising for ordinary bets is one click away. That has consequences:

18+ only. Betting accounts are for adults, without exception.
The temptation of "just one" ordinary bet. Anyone who tries to win back a mistake with an uncovered bet is no longer sure betting but gambling. This is exactly how problems start.
Budgets and limits. Decide in advance how much money you keep on betting accounts in total, and use the bookmakers' deposit limits.
Take warning signs seriously. If you spend more time or money than planned, hide losses or feel restless when you are not betting, get help.

Free and confidential help in Austria and Germany is listed on our responsible gambling page.

Summary

Legally, sure betting is sports betting and is subject to all the rules for it. In Germany, Slovakia and the UK that means gambling law; in Austria sports betting is formally not gambling under the GSpG, but it is regulated by the states' betting laws. Mathematically, the result does not depend on the match as long as every bet stands. In between are the residual risks you should know and take seriously. ArbVantage finds sure bets and works out the stakes; you decide and place every bet yourself.

FAQ

Is arbitrage betting gambling in Austria?

Not within the meaning of the federal Gambling Act. According to the Supreme Court, sports betting is not gambling under the GSpG because the outcome also depends on assessable factors. It is regulated by the betting laws of the federal states, and sure bets are ordinary sports bets.

Is arbitrage betting gambling in Germany, Slovakia or the UK?

Yes. Germany counts sports betting as gambling under the Interstate Treaty on Gambling, Slovakia under Act No. 30/2019 on gambling and the UK under the Gambling Act 2005. Sure bets are allowed, but only with operators licensed for that country.

Can I lose money with a sure bet?

Yes. If every bet is accepted at the shown odds and stands, the result is roughly the same whatever happens. But if odds change, a leg is voided or you make a mistake, a sure bet can end in a loss.

Do responsible gambling rules apply to sure bets?

Yes. Sure bets are sports bets: they are for adults only, and you should only stake money you can afford to lose. If you try to win back mistakes with uncovered bets, stop and get help.

Sources

As of October 2026. The calculations are illustrations under the stated assumptions. Not betting, financial, legal or tax advice. 18+.

Betting involves risk, sure bets included: odds move, bets get voided and accounts get limited. Only stake money you can afford to lose. If betting stops being fun, our responsible gambling page lists free help in Austria and Germany.