An accumulator rolls the returns from one selection into the next. A four-fold accumulator at even money on all four selections turns a £10 stake into £160. Change those odds to 2/1 each and the same £10 returns £810. The compounding effect is what makes accumulators seductive — and what makes them so difficult to land.

The mathematics are unforgiving. A four-fold with each selection at a 50% probability has a combined probability of 6.25%. Even if you’re a sharp handicapper running at 55% strike rate on singles, your four-fold wins just 9.15% of the time. Every leg you add halves your chances. This is why bookmakers promote accumulators so aggressively — the margin compounds in their favour with every selection.

If you’re going to bet accumulators, be methodical about it. Smaller folds — doubles and trebles — give you a realistic chance of collecting while still delivering meaningful returns. Use this calculator to compare the returns across different fold sizes before committing. A £10 treble at 3/1, 5/2 and 2/1 returns £540. That’s enough without needing a six-fold miracle.