152→ Odds
Surebet: the real numbers
A surebet promises a profit whatever happens. The calculator builds the split and then shows, with numbers, the four ways that profit shrinks or turns into a loss.
Best price for each outcome
Bets are rounded to
The chances add up to 96.4%, less than 100%. Spread the money like this and every outcome pays $10,373.
| Where | Odds | Bet | If it wins |
|---|---|---|---|
| Bookmaker A | 2.10 | $4,940 | $10,373 (+$373) |
| Bookmaker B | 2.05 | $5,060 | $10,373 (+$373) |
What can go wrong
1. Round amounts
With bets in steps of $100 the best split is $5,000 + $5,100.
+$355worst outcome after rounding
2. A stake limit
Everything shrinks to $6,073 in total.
+$227profit with the limit
3. A bet is voided
If Bookmaker A voids your bet and the result is the one you covered there, the other bets lose.
-$5,060worst case: from a sure-looking profit to a loss
4. The price moves
You already bet at Bookmaker A. Rebalancing the rest at the new price:
-$26Below odds 1.91 at Bookmaker B every outcome loses.
Bookmakers also cut or close accounts that do this often. That risk has no formula, but it is real.
Show the formula
Sum = 1 ÷ odds A + 1 ÷ odds B = 1 ÷ 2.10 + 1 ÷ 2.05 = 96.40%
Bet on each outcome = total × (1 ÷ odds) ÷ sum
Payout of every outcome = total ÷ sum = $10,373
Break-even price after a move = 1 ÷ (1 − sum of the other 1 ÷ odds)
When there is a surebet
sum of (1 ÷ odds) below 100%
Example: 1 ÷ 2.10 + 1 ÷ 2.05 = 96.4%. With $10,000 in total, any outcome pays $10,373: $373 more.
The plan, step by step
- Two bookmakersBookmaker A pays 2.10 on one outcome and bookmaker B pays 2.05 on the other.
- The splitYou put $4,940 with A and $5,060 with B. That way both sides pay the same.
- On paperYou collect $10,373 whatever happens: 3.7% on top of what you bet.
Four ways to lose the edge
| What happens | In the example |
|---|---|
| Stakes must be rounded to $100 | You keep $355 in the worst case |
| Bookmaker A accepts up to $3,000 | Everything drops to $6,073; you make $227 |
| One bet is voided and the other loses | You lose $5,060 |
| The price at B drops to 1.90 | You lose $26 on every outcome |
Worked out on the $10,000 plan. With B below 1.91 there is no way to come out ahead.
What it promises and what happens
On paper
- Both bets are accepted at the same time
- At the price you saw
- For the exact amount
In practice
- One goes in, the other lags
- The price changes in seconds
- Amounts get rounded or limited
Related
Questions
What is a surebet?
Combining prices from different bookmakers to cover every outcome of an event so that the chances add up to less than 100%. On paper you collect the same whatever happens.
Why is it not that sure?
Because the maths assumes everything goes perfectly. In the example, if one bet is voided and the other loses, you lose $5,060 chasing a profit of $373.
Is it legal to do surebets?
It depends on the laws where you live and on each bookmaker's rules. This page only does the maths and gives no legal advice.