Enter the best decimal odds you can find on each outcome plus the total stake you want to commit. The calculator adds up the inverse odds to test whether an arb exists, splits your money between the two bets, and shows the return from each side. Anything under 100% is an arbitrage.
How an Arbitrage Bet Works
Two bookmakers pricing the same match will sometimes disagree enough that their best prices, taken together, cover every outcome for less than the payout. Adding 1 ÷ odds for each outcome measures it. A single bookmaker’s own market sums above 100% because the margin is baked in, and the arb appears only when you cherry-pick across books.
Once the sum drops below 100%, the split is arithmetic. You divide the total stake in proportion to each outcome’s inverse odds, and both legs return the same amount, so the result of the match stops mattering to your P&L.
A Worked Example
A two-way market where the best price on each side sits with a different bookmaker: 2.10 and 2.08.
- Sum of inverse odds: 1 ÷ 2.10 + 1 ÷ 2.08 = 0.9570, or 95.70%.
- Margin: 100% – 95.70% = 4.30%, so an arb exists.
- Stake on the 2.10: $497.61 from a $1,000 total, returning $1,044.98.
- Stake on the 2.08: $502.39, also returning $1,044.98.
- Locked-in profit: $44.98 either way, 4.50% of the outlay.
The two percentages describe the same gap from different angles. 4.30% is how far the market falls short of 100%; 4.50% is what that shortfall pays on the money you put up. Return goes up faster than the shortfall because you only need to cover 95.70 cents to collect a dollar.
Reading the Stake Split
The uneven split is doing real work. $497.61 against $502.39 looks close to a coin toss, and swapping to $500 on each side breaks the equality: the 2.08 leg would return $1,040 and the 2.10 leg $1,050, turning a locked position into a small bet on one outcome.
Return figures matching to the cent is the check that the split is right. If your calculator shows two different returns, either a price has moved or the stakes have been rounded to something the bookmaker’s minimum bet forced on you.
Profit as a percentage of outlay is the number to compare across opportunities. 4.50% on $1,000 ties up the full grand for however long the market takes to settle, which is the cost most arb tables leave out.
The Gap Between Finding an Arb and Banking One
Three things stand between the calculator output and the money.
Bookmakers watch for the pattern. Consistent arbing draws stake limits and account closures, and a bettor whose maximum bet has been cut to $12 cannot place the $497.61 leg at all. The 4.50% edge disappears the moment one of your two accounts stops accepting a full stake.
Prices move while you are placing. The second leg is the exposed one. Get the 2.10 on and watch the 2.08 shorten to 2.00 before you confirm, and the market now sums above 100%, leaving you with a live bet rather than a locked position. Arbs on in-play markets shift fastest, and the ones that sit still for ten minutes are usually attached to a price the bookmaker is about to void.
Stake precision is the quiet one. Minimum stakes, maximum stakes and whole-unit rounding all push your split away from $497.61 and $502.39. Round the wrong way on a 4.30% market and a meaningful slice of the $44.98 goes with it.
Beyond the Price Gap
Arbitrage extracts money from disagreement between two bookmakers without needing an opinion on the football. The other route is having a better probability than the price implies, which is what Gecko Edge produces: Poisson goal models with a Dixon-Coles correction, blended with market and league priors, run across 130+ leagues, with the Expected Value Calculator and the No-Vig Calculator covering the arithmetic on this site.
Further Reading
- All betting calculators: the full library of 34 free tools
- Orbit Exchange review: professional exchange betting through a broker
- The relationship between market odds and fair price
What is an arbitrage bet?
An arbitrage covers every outcome of a market at prices that sum, in probability terms, to less than 100%. Backing 2.10 with one bookmaker and 2.08 with another gives 1 ÷ 2.10 + 1 ÷ 2.08 = 95.70%, so a $1,000 outlay split $497.61 and $502.39 returns $1,044.98 whichever side wins.
Is arbitrage betting worth it?
The margins are thin and the capital commitment is heavy. The example on this page returns $44.98 on $1,000 tied up until the match settles, which is 4.50% for one market. Bettors who make it work run many accounts and place quickly, and they accept that stake limits will eventually close some of those accounts.
Why do arbitrage opportunities disappear so quickly?
Odds compilers move prices as money arrives, and the disagreement that creates an arb is what both sides are trying to correct. A market at 95.70% is one price change away from summing above 100%. The exposure sits on your second leg, so the risk is placing one bet and finding the other price gone.
Can bookmakers close your account for arbitrage betting?
They can and they do. Bookmaker terms let them limit stakes or close accounts, and repeated bets at the top of the market on both sides of a fixture is a pattern their trading teams look for. Most arbers treat account life as a resource that runs down, which is part of the true cost of the strategy.