Arbitrage Calculator
What is sports betting arbitrage?
An arbitrage calculator finds the exact stakes you need to place on all outcomes of an event to guarantee a profit regardless of the result. Enter the best odds available for each outcome across different bookmakers — the calculator tells you how much to bet on each side and what your guaranteed return will be.
How to calculate an arbitrage bet
Convert each set of odds to an implied probability by dividing 1 by the decimal odds. Add all the implied probabilities together. If the total is below 1.00 (100%), an arbitrage exists. The profit margin is 1 minus the total implied probability. To calculate your stake per outcome, divide your total stake by the total implied probability, then multiply by each individual implied probability. The calculator above does this automatically for two- or three-outcome events.
Two-way vs three-way arbitrage
A two-way arb covers two outcomes — typically used for tennis, basketball or NFL (home win/away win). A three-way arb covers three outcomes and is common in football (soccer): home win, draw and away win. Three-way arbs require three different bookmaker accounts and are harder to execute before odds move, but they appear more frequently because the extra outcome creates more room for bookmaker pricing discrepancies. Use the toggle above to switch between modes.
Risks of arbitrage betting
The main practical risk is account restriction. Bookmakers actively identify and limit or close accounts of known arbitrage bettors because arbing is unprofitable for them. Other risks include odds moving between placing your bets (leaving you with a one-sided position), stake limits preventing you from getting the full amount on, and input errors leading to the wrong stakes. Always double-check your calculations before placing and act quickly once you identify an opportunity.
Is arbitrage betting legal in Ireland?
Yes. There is no law in Ireland that prohibits arbitrage betting. It is a legitimate strategy of placing ordinary bets with licensed bookmakers. The only consequences are commercial — bookmakers can restrict your account as a private business decision. Using GRAI-licensed bookmakers means you are betting within Ireland's regulated framework. See our GRAI-licensed bookmakers list for operators authorised to take bets from Irish customers.
Frequently Asked Questions
Placing bets on all outcomes of an event across different bookmakers so that you profit regardless of the result, exploiting differences in the odds offered.
Yes — no law prohibits it. Bookmakers may restrict or close accounts of customers they identify as arbitrage bettors, but it is fully legal.
Add up 1/odds for each outcome across your bookmakers. If the total is below 1.00 (100%), an arbitrage opportunity exists. The calculator above does this instantly.
Another name for an arbitrage bet — a wager where the mathematics guarantees a profit regardless of which outcome occurs.
Margins are usually 1–5% per bet. The profit is small but risk-free. Volume and fast execution across multiple accounts are key to making it worthwhile.