What the numbers mean and when to act.
Arbitrage %
What is the arb percentage?
The arb % is the sum of the implied probabilities for each side. If it's below 100%, an arbitrage exists — you can guarantee a profit by staking on all outcomes. If it's above 100%, the book has an overround (vig) and there's no guaranteed profit. Formula: arb% = (1/dec₁ + 1/dec₂) × 100
Stake Sizing
How stakes are calculated
Each side's stake is sized proportionally so that the payout is identical regardless of which outcome wins. Formula: stake₁ = total × (1/dec₁) / arb%. The guaranteed profit is your total bankroll minus the sum of all stakes — which is the same no matter which side wins.
3-Way Markets
When to use 3-way mode
Use 3-way for soccer (home / draw / away), some tennis formats, or any market with three distinct outcomes. The math is identical — just three implied probabilities summed. Soccer 1X2 markets offer more arb opportunities because draw odds are volatile and books often disagree on them significantly.
Practical Tips
Before you place the bets
Move fast: arb windows close in minutes. Have both sportsbook accounts funded before you start. Place the larger stake first (the favorite side). Confirm final odds at the book — prices can shift between calculation and placement. Watch for withdrawal limits on accounts that arb frequently.