Check prices and allocate a stake
A theoretical betting arbitrage exists when the sum of the inverse decimal odds for every mutually exclusive outcome is below 100%. This tool allocates stake in proportion to those inverse odds.
Formula and worked example
Inverse sum = Sum of (1 / Decimal odds)
Outcome stake = Total stake x (1 / Outcome odds) / Inverse sum
Equalised return = Total stake / Inverse sum
Two opposing outcomes at 2.10 each have an inverse sum of 95.24%. A total stake of 100 allocates 50 to each side, giving an equalised theoretical return of 105 and a theoretical ROI of 5%.
Execution risk matters
The calculation assumes every displayed price is available, accepted and settled under compatible rules. Price movement, stake limits, rounding, account restrictions, delays and void rules can remove a narrow theoretical margin before all bets are placed.
UK-licensed operators must publish rules covering voids, errors, withdrawals, maximum payouts and settlement. See Gambling Commission LCCP 4.2.6. Check the rules and final prices for every leg.
Limits and responsible use
Theoretical arbitrage is a mathematical condition, not guaranteed profit. The tool does not place bets or verify price availability. Set a spending limit before gambling and do not chase losses. Read GambleAware's advice and our responsible gambling guidance.
Related tools and guides
After checking all prices and rules, you can compare betting partners. Oddly Likely may earn a commission from partner links; check current odds, eligibility and terms. Read the affiliate disclosure.
Sources
- Gambling Commission, LCCP condition 4.2.6. Current code accessed 30 July 2026.
- GambleAware, Advice to consider if you're gambling. Accessed 30 July 2026.