Accumulator returns follow one simple rule: multiply each leg's decimal odds together, then multiply by your stake.
Step-by-Step Calculation
- Convert all odds to decimal format. Fractional odds like 5/1 become 6.00 (add 1). Odds of 4/6 become 1.67.
- Multiply the decimal odds of every selection. For a treble at 2.00, 1.80, and 2.50: 2.00 x 1.80 x 2.50 = 9.00.
- Multiply the combined odds by your stake. A £10 stake at combined odds of 9.00 returns £90 total (£80 profit + £10 stake).
Worked Example: Four-Fold Acca
| Leg | Selection | Decimal Odds |
|---|---|---|
| 1 | Arsenal to win | 1.65 |
| 2 | Over 2.5 goals -- Liverpool v Chelsea | 1.90 |
| 3 | Man City -1 AH | 2.10 |
| 4 | Both teams to score -- Spurs v Newcastle | 1.75 |
Combined odds: 1.65 x 1.90 x 2.10 x 1.75 = 11.52
A £5 stake returns £57.60 if all four legs win.
Why Each Leg Multiplies Risk
Each selection you add does not just increase the potential payout -- it compounds the probability of losing. A single bet at 2.00 has a 50% implied probability. Two such bets combined drop to 25%. By five legs, your implied chance is just 3.1%.
Using an Online Acca Calculator
Most bookmakers and third-party sites offer free accumulator calculators. Enter each selection's odds and your stake, and the tool computes the return instantly. These tools also handle each-way accas, dead heats, and rule-4 deductions -- calculations that become complex by hand.
Quick Reference Formulas
- Total return = Stake x (Odds1 x Odds2 x ... x OddsN)
- Profit = Total return - Stake
- Implied probability = 1 / Combined decimal odds
Understanding these formulas means you can sense-check any accumulator before placing it -- whether you are building a weekend football acca or a cross-sport multi.