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Arbitrage
calculator.

Two bookmakers offering opposite outcomes at prices that imply less than 100% combined probability? That's an arb. The calculator works out whether the maths is real, and exactly how to distribute stakes to lock in guaranteed profit.

Calculator

Two-way arbitrage

Enter the best decimal odds for each side of a market across different bookmakers.

Enter both odds and total stake to check for arbitrage opportunity

What this calculator does

If two bookmakers price a two-outcome market with combined implied probability under 100%, an arb exists. The calculator: (1) detects whether the maths produces an arb, (2) splits your total stake across both outcomes in proportion to the odds, so the return is identical regardless of which outcome wins, (3) shows your guaranteed profit and ROI percentage.

Worked example: Outcome A at 2.10 (47.6% implied) and Outcome B at 2.05 (48.8% implied). Combined: 96.4% — that's a 3.6% arb. With R1,000 total stake: R493.83 on A, R506.17 on B. Whichever wins, you get back R1,037.04, locking in R37.04 profit (3.7% ROI).

The realities of arbing

Margins are small

Real arbs are typically 1-3% on the total stake. To make R1,000 profit you need R30,000-R100,000 in combined stakes. That's significant capital tied up across multiple bookmaker accounts.

Detection is fast

Bookmakers run sophisticated detection. Sharp bet patterns — round-number stakes that mathematically match opposite-side stakes elsewhere, rapid placement, shared devices/IPs — flag accounts. Stake limits drop to R20-R50 within weeks. Accounts get closed.

Prices move

Between placing leg 1 and leg 2, the odds at the second bookmaker can shorten — killing your arb. Speed matters; manual arbing on phones often fails because the second leg is gone by the time you've placed it.

Voided bets are catastrophic

If a tennis match is abandoned, a horse withdrawn, or a rule change voids one leg, you're suddenly holding a one-sided bet at potentially terrible prices. This is the biggest single risk in arbing.

For most SA bettors

Arbing is a fascinating area of betting maths but rarely worth the operational complexity. For 99% of recreational SA punters, the time spent identifying and placing arbs would produce more profit applied to standard value betting on a single bookmaker. The calculator above is educational — it shows you when an arb exists. Whether to actually pursue it is a separate question with significant downsides.

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Common Questions

You asked.

Arbitrage betting (or 'arbing') is placing bets on every possible outcome of an event across different bookmakers, where the prices add up to less than 100% implied probability. The result is a guaranteed profit regardless of outcome — typically 1-5%. The catch: arbs are rare, small, and bookmakers actively detect and limit accounts that engage in them.

Arbitrage betting is legal — you're placing two legitimate bets at two licensed bookmakers. However, every SA bookmaker's terms of service allow them to close, restrict or limit accounts they identify as arbing. Most bookmakers detect arbs through stake patterns, rapid bet placement across markets, and shared device/IP fingerprints. Stake limits or account closure typically follow. The activity is legal; sustaining it is operationally hard.

Most arbs offer 1-3% profit on the total stake. R10,000 in combined stakes might yield R200 profit. To make meaningful money requires huge bankroll spread across many bookmaker accounts, fast execution before prices change, and tolerance for accounts being limited. For most SA bettors, arbing is technically possible but not practically worth the operational complexity. The exception is very high-volume professional bettors with dedicated infrastructure.

Five key risks: (1) Account limitations — bookmakers cap your max stake to a few Rand once they identify you. (2) Voided bets — if one leg gets voided (rule change, abandoned event), the other side becomes a one-sided bet. (3) Price movement — odds can shift between placing leg 1 and leg 2, killing the arb. (4) Stake errors — miscalculated stake distributions can turn a guaranteed profit into a loss. (5) Bonus restrictions — some bookmakers void winnings if they identify bonus-related arbing.