Parlay insurance calculator
What a parlay is worth when the book refunds your stake as a bonus bet if exactly one leg loses.
Result
- Parlay odds
- +596
- Fair chance every leg wins
- 12.5%
- Chance exactly one leg loses
- 37.5%
- Refund, as a bonus bet
- $25.00
- The parlay on its own
- -$3.28
- The refund adds
- $6.56
- Expected value
- $3.28
Worth it: positive expected value
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How it works
Parlay insurance refunds your stake when a parlay loses by exactly one leg. The refund is a bonus bet, usually capped, so it's worth what you can convert it for: about 70% of face value.
The calculator adds two things: the parlay's own expected value at your book's price, and what the refund adds. To get each leg's fair chance, it takes the book's margin out of the leg's price. Use 4.8% for a standard -110 market, or work out the real figure with the de-vig calculator.
It treats the legs as independent. Legs from the same game move together, which changes how often exactly one of them loses. Minimum legs, minimum odds, and the refund cap vary by offer, so check your book's current terms.
How much is parlay insurance worth?
The calculator above starts with an example: a $25 parlay of three -110 legs, with a refund of up to $25. With the margin removed, each leg is close to a coin flip, so the parlay wins 12.5% of the time and is worth -$3.28 on its own.
Exactly one leg loses 37.5% of the time. Each time, a $25 bonus bet comes back, worth $17.50 at a 70% conversion, so the refund adds $6.56 on average. Together the insured parlay is worth $3.28.
Does adding legs make parlay insurance better?
No. More legs make the one-leg-loses case rarer while the parlay's own margin grows. With the same numbers, four legs is worth $0.10, five legs -$2.49, and six legs -$4.49. What is parlay insurance, and what is it actually worth? walks through why.
The cap matters too. Stake $100 on the four-leg parlay with the same $25 cap and it's worth -$12.73: the parlay's own cost grows with the stake and the refund doesn't.
More detail: What is parlay insurance, and what is it actually worth?.