Odds Format
Total Stake ($)
Number of Outcomes
Outcome 1 Odds
Outcome 2 Odds
Results
Enter total stake and odds for all outcomes to see results.
What this calculator does
Bookmakers don’t always agree on prices. Occasionally the best odds for every outcome of a match, taken from different bookmakers, add up to a small gap in your favour. Back every outcome with the right split of stakes and you get the same return whatever happens. That’s an arbitrage, or “surebet”.
The calculator tells you whether your prices create one, how big the margin is, exactly how to divide your money between the outcomes, and what comes back.
It works for two-outcome markets (over/under goals, both teams to score, draw no bet) and three-outcome markets (home/draw/away). Real arbitrage gaps are small and usually close within minutes.
Step by step
The maths behind it
A total under 1.00 (100%) means the prices leave room for an arbitrage.
How to split the money:
You enter the prices yourself. The tool doesn’t pull odds from bookmakers.
Worked examples
Site A offers 2.10 on over 2.5. Site B offers 2.02 on under 2.5. Book % = 0.4762 + 0.4950 = 0.9712. With $1,000 to spread:
The best prices you can find are home 2.45, draw 3.40 and away 2.95. Book % = 0.4082 + 0.2941 + 0.3390 = 1.0413.
This is the normal situation. The 4% above 100% is the bookmakers’ margin.
BTTS Yes is 1.95 at one bookmaker and BTTS No is 2.12 at another. Book % = 0.5128 + 0.4717 = 0.9845. On $500:
Small margins like this disappear if either price moves before both bets are placed.
Questions people ask
QIs arbitrage betting allowed?
Placing bets that happen to cover every outcome isn’t illegal in most countries. Bookmakers do watch for it, though, and often restrict the accounts of people who do it regularly. Always check the operator’s terms.
QWhere do the price gaps come from?
Bookmakers set and move their odds independently. After team news or a big bet, one may adjust before another. Comparing the same market across several sites is the only way to spot a gap.
QWhat can go wrong?
A price changes after you place the first bet. A bookmaker voids or limits your stake. Two sites apply different rules to the same market. You make a staking mistake. Any of these turns a “sure” profit into a loss, so arbitrage is never truly risk-free.
QHow big are typical margins?
Usually somewhere around 1–3%. Gaps above 5% are rare, and often a sign that one of the prices is a mistake that will be cancelled.
