Arbitrage Betting Calculator

An arb exists when the sum of implied probabilities across all outcomes is less than 100%. This happens when different bookmakers price the same event differently.

Step-by-step example:

Outcome A (Bookmaker 1): 2.10 → Implied: 47.6%

Outcome B (Bookmaker 2): 2.05 → Implied: 48.8%

Total: 96.4%

Since 96.4% < 100%, a 3.6% guaranteed profit exists. The arb calculator above converts this directly to exact stakes for each side.

Knowing an arb exists isn't enough — you need the right stake split to guarantee the same profit regardless of which outcome wins.

Arbitrage Stake Formula:

Stake on Outcome A = (Total Stake × Implied Prob A) / Total Implied Prob

Example with $1,000 total stake:

- Outcome A at 2.10 (implied 47.6%)

- Outcome B at 2.05 (implied 48.8%)

- Total implied: 96.4%

Stake on A: (1000 × 0.476) / 0.964 = $494

Stake on B: (1000 × 0.488) / 0.964 = $506

Regardless of result, you collect ~$1,036 — a $36 guaranteed profit on $1,000 staked.

The arb calculator handles this math automatically.

2-Way markets (tennis, basketball, most American sports) are the most common for arbing. There are only two outcomes to cover.

3-Way markets (soccer match result: Home / Draw / Away) require covering three outcomes across up to three different sportsbooks. The math is the same principle — total implied probability must be under 100% — but finding three mis-priced outcomes simultaneously is harder and requires more accounts.

Best markets for arbing:

- Tennis (2-way, no draw)

- Basketball (2-way with moneyline)

- Head-to-head prop bets

- Futures (if you can find consistent mispricing)

The calculator currently handles 2-way markets. For 3-way arbs, run the implied probability check manually or use a dedicated arb finding tool.

Pure arbitrage betting carries no mathematical risk — if you execute correctly, you profit regardless of outcome. But there are practical risks:

1. Odds movement — Between placing your first and second bet, the odds can shift, turning your arb into a regular (potentially losing) bet.

2. Account limitations — Sportsbooks actively monitor for arbing behavior. If they detect it, they'll limit your maximum stake or close your account. Soft books (DraftKings, FanDuel, BetMGM) are fastest to limit; sharp books (Pinnacle) are more tolerant.

3. Withdrawal issues — Some sportsbooks have rollover requirements or bonus terms that complicate withdrawing arb profits.

4. Human error — Entering the wrong stake or odds on one leg converts an arb into a one-sided position.

Mitigation: Use reliable arb finding software, act quickly, keep stakes reasonable relative to your account history, and use the tracker to log every bet.