Bet builder calculator
Enter each leg's chance (or its single odds) and the calculator gives the slip's fair odds — the price where it breaks even. Add your bookmaker's price to see whether it's value. The example is a real slip from our record.
Why bet builders are rarely priced fairly
Every leg in a bet builder carries the bookmaker's margin, and multiplying the legs multiplies the margins. If each of three legs is priced 10% under fair, the slip ends up about 25% under fair. On top of that, legs in the same match are connected — when a team dominates, all its attackers tend to get shots away — and bookmakers adjust for that too, which is why a bet builder price is often lower than the singles multiplied together.
The example above shows the difference. Multiplying its three legs gives fair odds of 5.92; our model, which links team-mates on the same side, priced the same slip at 5.79 — the link makes it a little more likely to land, so its fair price is a little lower.
This calculator treats the legs as independent, which is the simple, conservative sum. Our own model prices team-mates together, so the fair odds on our slips allow for the link between them. How bookmakers price bet builders →
Questions
How do I calculate bet builder odds?
Turn each leg into a chance (1 divided by its decimal odds), multiply the chances together, then divide 1 by the result. That gives the fair odds if the legs are independent. A bookmaker's actual bet builder price is usually lower, because of margin and the link between legs in the same match.
What is a good bet builder price?
Any price above the slip's fair odds. If the fair odds are 5.00 and your bookmaker offers 5.50, you're getting 10% more than the bet is worth; if it offers 4.00, you're getting 20% less.
More free tools
- Odds converter — Fractional, decimal, American and implied probability — convert any price instantly.
- Bookmaker margin calculator — See how much margin is built into a market, and the fair odds once it's taken out.
- Value bet calculator — Compare a bookmaker's price with the fair price and see the edge and expected profit.
- Arbitrage calculator — Two or three outcomes, back or lay: exact stakes for a guaranteed profit.