Multi & Same-Game Multi Margin Calculator (AUD)

Every leg of a multi carries the bookmaker’s margin, and those margins compound. A multi or same-game multi (SGM) that looks like a few small edges stacked together is actually one large edge — in the bookmaker’s favour.

Enter the number of legs and the typical margin per leg, and this calculator returns the compounded total margin, the book’s expected hold, and the cost on a stake you choose.

How it works

If each leg carries margin m, an N-leg multi carries (1 + m)ⁿ − 1. A 5% margin on a single bet becomes about 22% across four legs — the same reason a long accumulator is so hard to beat even when every leg looks fair.

Same-game multis are typically priced with even fatter per-leg margins (and correlation adjustments), so the compounded cost is usually higher than this baseline. Use it to see the floor of what an SGM is costing you.

total margin = (1 + per-leg margin)^legs − 1

FAQ

Why is a multi worse value than singles?

Because the bookmaker’s margin on each leg compounds. Four 5% legs aren’t 5% — they’re about 22% combined, so the longer the multi the bigger the built-in edge against you.

Are same-game multis (SGMs) worse?

Usually, yes. SGM legs are typically priced with higher margins and correlation adjustments, so the real cost is often above the compounded baseline this calculator shows.

How do I find the per-leg margin?

Use the overround calculator on each leg’s market: book percentage minus 100% is the margin. Then bring the typical figure here to see the multi’s compounded cost.

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