Free tool
Accumulator calculator.
Every leg has to win, and the odds multiply. This gives the combined price and the return — and, quietly, the true probability you're actually backing.
Every leg compounds the margin. The combined odds look generous because they multiply — but so does the bookmaker's edge on each leg, and the true probability shrinks fast. This shows the return honestly; it can't make a long-odds accumulator a good bet.
The worked example
A £10 treble on selections at 2.0, 1.5 and 3.0 gives combined odds of 9.0 (2.0 × 1.5 × 3.0). The return if all three win is £90, a £80 profit. But the true implied probability is 1 ÷ 9.0 = 11.1% — all three landing is a one-in-nine shot before any margin is stripped out.
Straight answers
How do you calculate accumulator odds?
Multiply the decimal odds of every selection together. A treble of 2.0, 1.5 and 3.0 is 2.0 × 1.5 × 3.0 = 9.0, so a £10 stake returns £90. Every leg must win for the accumulator to pay.
Why do accumulators pay so much?
Because the odds compound — but so does the risk. The combined price also compounds the bookmaker's margin on every leg, which is exactly why accumulators are one of the highest-margin products a bookmaker offers.
Are accumulators worth it?
Mathematically an accumulator's implied probability is the product of each leg's implied probability, so its true chance is small and the compounded margin is large. This calculator shows the return; whether stacking that many legs is a good idea is a separate, honest question.
What is the difference between a double, treble and accumulator?
A double is two selections, a treble is three, and an accumulator (acca) is four or more — all requiring every leg to win. This tool handles any number from two upward.
Multiplying odds is arithmetic. Knowing the true chance you've stacked is the honesty.
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18+ · Education, not betting advice · No tips, no picks · BeGambleAware.org
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