Can you win at sports betting long term? The maths behind the honest answer

The margin: a headwind on every bet

A bookmaker's odds add up to more than 100% implied probability. The excess is the margin, and it is what the bookmaker expects to keep. Take a tennis match between two equally strong players, priced at 1.90 each:

1 ÷ 1.90 + 1 ÷ 1.90 = 0.5263 + 0.5263 = 1.0526 → overround 5.26%
expected return per €1 on either side = 0.5 × 1.90 − 1 = −€0.05

Every bet on that match loses 5 cents per euro on average. To break even at 1.90 you need to win 1 ÷ 1.90 = 52.6% of such bets, not 50%. You aren't betting against the other punters; you're betting against a price with a built-in cost.

Now suppose someone places 1,000 bets of €10 on coin-flip matches like this, with no edge at all:

Normal approximation; each bet wins €9 or loses €10 with equal probability, a standard deviation of €9.50 per bet. The spread grows with the square root of the number of bets, the expected loss grows in a straight line.

That table explains most of what people experience. After a hundred bets, luck dominates and many are ahead, which feels like skill. After thousands of bets, the margin dominates. Our guide to market efficiency explains why prices are hard to improve on in the first place.

Why most bettors lose

• The margin compounds in accumulators. If each leg of a five-fold returns 95% on average, the accumulator returns 0.95⁵ ≈ 77%: an expected loss of about 23% of the stake, and margins on popular accumulator markets are often higher.
• Long shots are priced worse. Research on football betting finds a favourite-longshot bias: outsiders tend to be worse value than favourites, and that is where many recreational bets go.
• Information is already in the price. Form, injuries and line-ups are known to the bookmaker and to professional bettors whose money moves the line.
• Short-term wins mislead. A good month says little; see the table above. People raise stakes after a lucky run and chase losses after a bad one.

The narrow exceptions

There are approaches with a positive expected value. None of them is about picking winners better than the market.

• Price differences between bookmakers. When two bookmakers disagree enough on the same market, backing every outcome at the best price adds up to less than 100%. That is a sure bet: if every leg is placed at the shown odds and stands, the payout is about the same whatever the result, typically 1% to 2% of the combined stake. A small margin, not a guarantee.
• Bonuses and free bets. Promotions are a marketing cost for the bookmaker. Converting a free bet into cash, covered in our free bets guide, has a positive expected value, but each offer works only once.
• Prices above a sharp consensus. Value betting backs prices that are higher than the market's best estimate of the true probability. Positive on average, but with real losing runs. In ArbVantage, value bets are coming soon.
• Genuinely better models. A small number of bettors build models that beat the closing line in specific markets. It is real, rare, and takes a large amount of work and data.

Our comparison of betting strategies puts these next to the popular systems by maths, variance, effort and capital.

Why even the exceptions are limited

• Limits. Recreational bookmakers restrict accounts that win consistently, at some within weeks, at most within months. Maximum stakes can fall to a few euros. See bookmaker limits.
• Small margins need turnover. At about 1% per sure bet, the money has to be staked many times. That takes capital spread over several accounts and time every day.
• Things go wrong. Prices move before the second leg, bets are voided, rules differ between bookmakers. Each of these can eat the margin of many bets.
• Promotions run out. Welcome offers are one per person, and bookmakers stop sending offers to customers who only take them.

What is realistic

For ordinary betting on your own opinions: expect to lose roughly the margin over time, and treat it as the price of entertainment. For price-based methods, think in turnover, not wins. What would €1,000 a month take? At a 1% average margin, about €100,000 in stakes a month: roughly 167 sure bets of €600, more than five a day. Most people never get there, because bookmakers limit winning accounts. Use the calculator with your own numbers, and judge your results by your records, not your memory: ROI and yield shows how.

When to stop

Betting is never a way out of money problems. Stop and talk to someone if you bet more than you planned, chase losses, borrow to bet, hide your betting, or feel restless when you can't bet. In Austria and Slovakia, bookmakers offer deposit limits and self-exclusion, and free, confidential counselling is available. Our responsible gambling page lists where to get help.

Frequently asked questions

Are there professional sports bettors?

Yes, but very few, and most of them don't win by picking teams. They exploit price differences between bookmakers, promotions or detailed models in specific markets, they keep strict records, and they constantly deal with stake limits. For most people who bet regularly, the long-term result is negative.

Is sports betting luck or skill?

Both, on different timescales. Over dozens of bets luck dominates, so a winning month proves little. Over thousands of bets the margin dominates, and only a real, measurable edge on price can overcome it. Legally, Austria does not treat sports betting as gambling under the federal Gambling Act; that says nothing about whether you can win.

What is realistic for an ordinary bettor?

Betting on your own opinions, expect to lose about the bookmaker margin over time. Price-based methods such as sure bets can have a small positive margin, but results depend on turnover, capital, time and limits, and they can be negative. Check everything against your own records.

Sources

• Forrest, D., Goddard, J., Simmons, R. (2005): Odds-setters as forecasters: The case of English football. International Journal of Forecasting 21(3), 551–564
• Cain, M., Law, D., Peel, D. (2000): The favourite-longshot bias and market efficiency in UK football betting. Scottish Journal of Political Economy 47(1), 25–36
• Levitt, S. D. (2004): Why are gambling markets organised so differently from financial markets? The Economic Journal 114(495), 223–246
• RIS: Glücksspielgesetz (GSpG), § 1 definition of gambling
• Spielsuchthilfe (Austria): counselling for gambling problems

As of October 2026. All figures are worked examples with the stated assumptions.

Betting involves risk, including sure bets: prices move, bets get voided and accounts get limited. Only bet money you can do without. Our responsible gambling page lists free, confidential help.

Not betting, financial, legal or tax advice. 18+. As of October 2026.