Arbitrage Calculator
Enter the highest available odds for each outcome from different bookmakers. The calculator detects if an arbitrage opportunity exists and computes the optimal stake split.
| Outcome | Stake | Return if wins |
|---|---|---|
| Outcome A | 49.40 | 103.73 |
| Outcome B | 50.60 | 103.73 |
What is the Arbitrage Calculator?
An arbitrage (or arb / surebet) exists when the best odds across different bookmakers for each outcome combine to a sub-100% implied probability. By staking proportionally across all outcomes, you guarantee a profit regardless of which one wins. This calculator detects 2-way and 3-way arbs and computes the optimal stake split.
How to use the Arbitrage Calculator
- Enter your total stake to distribute.
- For each outcome (Home / Draw / Away or just Home / Away), enter the BEST odds you can find from any bookmaker.
- The calculator shows whether an arbitrage exists, the guaranteed profit margin, and the optimal stake per outcome.
- Place each stake at the respective bookmaker to lock in profit.
The formula
Inverse Sum = (1/Odds_A) + (1/Odds_B) + ... + (1/Odds_N)
Arbitrage exists if Inverse Sum < 1
Profit margin (%) = (1 − Inverse Sum) × 100
Optimal stake for outcome X = Total Stake × (1/Odds_X) / Inverse SumWorked example
You spot these prices for an England vs Senegal World Cup match:
- England to win @ 2.10 (Bet365)
- Draw @ 4.20 (Pinnacle)
- Senegal to win @ 4.50 (Betfair Exchange)
Inverse sum = 1/2.10 + 1/4.20 + 1/4.50 = 0.476 + 0.238 + 0.222 = 0.937
Since 0.937 < 1, arbitrage exists with a margin of +6.31%.
With $1,000 total stake:
- Bet $508.21 on England @ 2.10 → Returns $1,067.24
- Bet $253.96 on Draw @ 4.20 → Returns $1,066.63
- Bet $237.83 on Senegal @ 4.50 → Returns $1,070.24
Whatever happens, you get back ~$1,067 - a guaranteed profit of ~$67 (6.7%).
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Frequently Asked Questions
How often do real arbitrage opportunities appear?
Frequently for sharp users — small arbs (0.5-2% margin) appear daily across major football markets. They vanish in seconds as bookmakers update their lines. Higher margins (3-5%+) are rare and usually disappear before you can place all the legs.
Are bookmakers OK with arbitrage betting?
Recreational bookmakers (Bet365, William Hill, etc.) often restrict or close accounts that consistently arb. Sharp books (Pinnacle, Betfair Exchange) welcome the volume. Most pros use multiple accounts and stake-size carefully to avoid limits.
How do I find arbitrage opportunities?
Subscribe to an arb-finder service like RebelBetting, OddsJam, or build your own using our [odds API](/odds-api) which returns prices from 4 bookmakers in one call.
What's the risk?
Stake fragmentation (one leg places, another doesn't before the line moves), bookmaker account restrictions, and market mistakes (e.g. a bookmaker voids the bet). The math is guaranteed; the execution isn't.
Can I arb on the same bookmaker?
No — a single bookmaker prices the market so that no single-book arb exists (their inverse sum is always > 1 by their margin). Arbs require different books with different opinions.
Is arbitrage legal?
Yes — it's legal everywhere sports betting is legal. It's not against any law to bet at multiple bookmakers and lock in profit. Individual bookmakers may not like it (see Q2) but it's legal.