Arbitrage (Surebet) Calculator
Check whether two bookmakers disagree enough to cover a market at a profit, and how to split the bank.
Arbitrage (Surebet) Calculator
Enter the best price for every outcome across bookmakers to see whether the market can be covered at a profit.
Arbitrage found — the market totals 95.24 %, leaving 4.76 % of guaranteed margin.
Arb %
95.24 %
Payout
₦10,500.00
Profit
+₦500.00
ROI
+5.00 %
| Bookmaker | Outcome | Odds | Stake | Returns |
|---|---|---|---|---|
| Bookmaker A | Home | 2.10 | ₦5,000.00 | ₦10,500.00 |
| Bookmaker B | Away | 2.10 | ₦5,000.00 | ₦10,500.00 |
Stakes are exact. Rounding them to whole naira, or a price moving before all legs are on, shifts the return between outcomes and can wipe out a thin margin.
What is Arbitrage Betting?
Arbitrage — or a surebet — means backing every outcome of a market at different bookmakers so that the total staked is less than the return, whichever result comes in. It is not a prediction: nothing about the match matters. The profit comes purely from two bookmakers pricing the same event differently.
The Formula
- Arbitrage percentage: Arb % = Σ (1 / Oᵢ)
- An arbitrage exists when Arb % < 1
- Stake on outcome i: Sᵢ = S × (1 / Oᵢ) ÷ Arb %
- Guaranteed profit: S ÷ Arb % − S
- ROI: (1 ÷ Arb % − 1) × 100 %
Example: Two Bookmakers
A tennis match. Bookmaker A prices Player 1 at 2.10; Bookmaker B has Player 2 at 2.10. Each implies 47.62 %, so the market totals 95.24 % — under 100, therefore an arbitrage.
- Bank: ₦10,000
- Stake on Player 1: ₦10,000 × 0.4762 ÷ 0.9524 = ₦5,000
- Stake on Player 2: ₦10,000 × 0.4762 ÷ 0.9524 = ₦5,000
- Return either way: ₦5,000 × 2.10 = ₦10,500
- Guaranteed profit: ₦500, an ROI of 5.00 %
Note how thin that is. A 5 % ROI on a bank you must have sitting at two bookmakers, on a price that may last minutes, is the realistic upper end rather than a typical case.
The Risks Nobody Advertises
The arithmetic is guaranteed; the execution is not. What actually goes wrong:
- Account limits and closures. This is the normal ending. Bookmakers detect arbitrage patterns quickly and respond by cutting your maximum stake to a fraction of what you want, or closing the account outright. It breaks their terms of service, so you have little recourse.
- Price movement between legs. Get one side on and the other moves, and you are left holding an ordinary bet on one outcome.
- Voided legs. A postponement or a rule difference between bookmakers can void one side while the other stands, breaking the cover.
- Rounding and limits. Stakes rounded to whole naira, or capped by a maximum, shift the return between outcomes and can erase a 2 % margin.
- Tied-up capital. The bank has to sit funded across several bookmakers to be usable at all.
Arbitrage is legal, but it is a business with real operational risk — not free money.
Frequently Asked Questions
How do I calculate an arbitrage between two bookmakers?
Add up 1 divided by each price. If the total is below 1 the market can be covered at a profit. Split your bank in proportion to those figures — stake = bank × (1 / odds) ÷ total — and every outcome returns the same amount. For 2.10 and 2.10 the total is 0.9524, so ₦10,000 becomes ₦5,000 on each side and returns ₦10,500 either way.
Is arbitrage betting legal in Nigeria?
Yes — placing bets at two licensed bookmakers breaks no law. It does, however, breach most bookmakers’ terms of service, and they enforce that commercially rather than legally: stake limits, voided bets and closed accounts are the normal response once a pattern is spotted.
Why are arbitrage opportunities so rare?
Because every bookmaker builds a margin into its prices. An arb only appears when two books disagree by more than their combined margins — usually for minutes, after team news or a large bet moves one line. Nigerian bookmakers price closely off the same feeds, so gaps are small and short-lived.
What can go wrong?
A price moving before you get all legs on leaves you exposed on one side. Stakes rounded to whole naira shift the return between outcomes. A leg can be voided — for a postponed match, say — while the others stand, turning a covered market into a single open bet. And a bookmaker can limit or close your account, which is the most common outcome for consistent arbers.
What is the difference from dutching?
Arbitrage covers every outcome of a market, usually across different bookmakers, and only makes sense when the total is under 100 %. Dutching covers a chosen subset of outcomes at one bookmaker and is a way of backing several runners for the same return — it carries real risk, because an outcome you did not back can win.
Related Tools
- Dutching Calculator — the same stake split applied to a subset of outcomes at one bookmaker.
- Bookmaker Margin Calculator — arbs appear where combined margins are lowest, so start by finding them.
- Implied Probability Calculator — the same 1 / odds arithmetic, per outcome.