Accumulator explained

The accumulator, or "acca" for short, is the classic betting slip. Several selections are combined and their odds are multiplied together. That turns small odds into big wins – but only if every single selection comes in. One wrong selection and the whole slip is lost.

Calculating the total odds

Total odds = odds 1 × odds 2 × odds 3 × …

If a match is postponed or a bet is voided, most bookmakers treat that match as odds of 1.00 – the accumulator carries on with the remaining selections.

Why accumulators are expensive

When the odds are multiplied, so are the margins. If each selection has a 5 per cent margin, a treble leaves on average only 0.95³ = 85.7 per cent as payout, five selections 77.4 per cent and ten selections just under 60 per cent. If you regularly play long accumulators, you pay a high price for the chance of a big win.

Conversely: if each individual selection has genuine value, that multiplies too. That is why accumulators are not bad in principle – they simply amplify what is in the individual selections, for better or worse.

Related selections

Many bookmakers do not allow two selections from the same match to be combined, because the events are linked (such as "home win" and "home team to score"). For such cases there are dedicated markets or "bet builders", where the bookmaker calculates the odds rather than simply multiplying them.

Practical tips

• Better a few well-reasoned selections than long lists.
• Variance is high: even good accumulators lose most of the time.
• If you want cover against a single slip-up, take a look at the system bet.