# Acca calculator: combined odds and return

> Work out the combined odds, return, profit and implied probability of an accumulator from your stake and odds in fractional (5/1) or decimal (6.00) form.

Source: https://beforeyouinstall.com/tools/accumulator-calculator/
Updated: 2026-11-07

The calculator multiplies the decimal odds of every selection to give the combined odds of an accumulator, then multiplies your stake by that number for the return. Combined odds = d1 × d2 × … × dn. It also shows the implied probability, 1 ÷ odds. Void legs, dead heat, Rule 4 and bonus terms are not counted. A worked example is below.

## Use the calculator

Inputs: a stake in € (more than €0) and 2 to 15 selections, each in fractional odds like 5/1 or decimal odds like 6.00 (1.01 or higher). Outputs: combined odds, return, profit and the implied probability.

The table below shows the same examples without the calculator.

**In short:** enter a stake and 2 to 15 odds; the tool multiplies them.

## The formulas

- **Fractional to decimal:** d = 1 + a ÷ b. Odds of 5/1 give 1 + 5 ÷ 1 = 6.00.
- **Combined odds:** the product of every decimal price, d1 × d2 × … × dn.
- **Return:** stake × combined odds. The return includes your stake.
- **Profit:** return − stake.
- **Implied probability of one selection:** 1 ÷ d. For 4.00 that is 25%.
- **Implied probability of the whole acca:** 1 ÷ combined odds.

An accumulator is one bet that joins two or more selections; the return depends on every selection winning. The implied probability is the odds restated as a percentage, so it includes the bookmaker's margin and is not a forecast.

**In short:** multiply the decimals, multiply by the stake, subtract the stake for profit.

## Six worked examples

**Accumulator examples with fractional or decimal odds. Numbers are illustrations, not tips. Source: formulas above · checked 7 November 2026**

| Example | Stake | Selections (as entered) | Combined odds | Return | Profit | Implied probability |
|---|---|---|---|---|---|---|
| 1 | €10.00 | 2/1 (3.00), 1/1 (2.00) | 6.00 | €60.00 | €50.00 | 16.67% |
| 2 | €10.00 | 1/2 (1.50), 1/1 (2.00), 1/4 (1.25) | 3.75 | €37.50 | €27.50 | 26.67% |
| 3 | €5.00 | 1.30, 1.50, 1.80, 2.00 | 7.02 | €35.10 | €30.10 | 14.25% |
| 4 | €20.00 | 4/5 (1.80), 11/10 (2.10) | 3.78 | €75.60 | €55.60 | 26.46% |
| 5 | €5.00 | 1/1 three times (2.00 each) | 8.00 | €40.00 | €35.00 | 12.50% |
| 6 | €10.00 | 1.20 six times | 2.99 | €29.86 | €19.86 | 33.49% |

Example 6 uses the unrounded product, 1.2 to the power of 6 = 2.985984, so €10 × 2.985984 = €29.86.

Example 1 in full: 2/1 becomes 3.00, 1/1 becomes 2.00, 3.00 × 2.00 = 6.00, €10 × 6.00 = €60.00.

**In short:** every extra selection multiplies the odds and lowers the implied probability.

## What the calculator does not count

- **Void legs.** The operator's rules decide how a void selection counts in an acca. We have not read them yet. See [void bets and Rule 4](https://beforeyouinstall.com/guides/void-bet-and-rule-4-meaning/).
- **Dead heat.** A tied result can cut a return; the operator's rules decide.
- **Rule 4.** A deduction from a payout after a non-runner; it is not applied here.
- **Each-way.** Each-way bets have two parts; see [each-way](https://beforeyouinstall.com/guides/each-way-meaning/).
- **Bonus terms.** Bet credits and bonus cash change what a return pays; see [bet credits and bonus cash](https://beforeyouinstall.com/guides/bonus-credits-vs-bonus-cash/).
- **Cash out, price boosts and BOG.** Not modelled.

Odds formats are covered on [odds formats explained](https://beforeyouinstall.com/guides/odds-formats-explained/). To read the same numbers on a slip, use [reading a bet slip](https://beforeyouinstall.com/guides/read-your-bet-slip-in-a-betting-app/).

**In short:** the result is the clean arithmetic; the operator's rules can change a real settlement.

## How we checked

- Formulas: standard arithmetic for decimal odds. Operator definitions of an accumulator and of void legs: Not checked in this build.
- Examples recalculated by script on 7 November 2026.
- We did not place bets or open accounts.

**In short:** the arithmetic is verified; operator-specific rules are not yet read.

## Help and limits

18+ only. Gambling can be addictive – play responsibly. Set limits, take breaks and never bet more than you can afford to lose.

Free 24/7 support: 1800 936 725 · gamblingcare.ie. Plan a limit with the [deposit limit planner](https://beforeyouinstall.com/tools/deposit-limit-planner/). More numbers are on the [Responsible gambling](https://beforeyouinstall.com/responsible-gambling/) page. Back to [all tools](https://beforeyouinstall.com/tools/).