Single and double bet calculator: how singles, doubles and accas pay out
How to work out the return and the profit on a single, double, treble or accumulator from fractional or decimal odds, with worked $ examples.
Every bet calculator starts with the same building blocks: the single and the double. Once you can work those out by hand, trebles, accumulators and even a Lucky 15 are just more of the same. This guide shows the sums with fractional and decimal odds, and the difference between your return and your profit.
Fractional and decimal odds
UK bookmakers show fractional odds like 5/2 by default, while most calculators work in decimal. Converting is one step:
| Fractional | Decimal | $10 returns |
|---|---|---|
| 1/2 | 1.50 | $15 |
| 4/5 | 1.80 | $18 |
| Evens (1/1) | 2.00 | $20 |
| 5/4 | 2.25 | $22.50 |
| 6/4 | 2.50 | $25 |
| 2/1 | 3.00 | $30 |
| 5/2 | 3.50 | $35 |
| 10/1 | 11.00 | $110 |
The "+ 1" is your stake coming back. Fractional odds show profit only; decimal odds include the stake.
Single bet calculator
A single is one selection. If it wins, you're paid at the odds; if it loses, you lose the stake.
$10 on a 5/2 shot: $10 × 3.5 = $35 returned. Your profit is $35 − $10 = $25, which is also $10 × 5/2. When a bookmaker's bet slip says "potential returns", it means the total including your stake.
Double bet calculator
A double is one bet on two selections. Both must win, and the winnings from the first roll on to the second, so you multiply the decimal odds.
$10 double on 5/2 (3.5) and 6/4 (2.5): $10 × 3.5 × 2.5 = $87.50 returned, $77.50 profit. If either loses, the whole bet loses.
Double vs two singles
Split the same $10 into two $5 singles on the same selections and compare:
- Both win: singles return $17.50 + $12.50 = $30; the double returns $87.50.
- Only the 5/2 wins: singles return $17.50; the double returns nothing.
- Neither wins: both lose $10.
The double pays far more when everything wins and nothing when one leg fails. Neither is "better"; they carry different risk.
Trebles and accumulators
A treble is three selections and an accumulator (acca) is four or more. The maths is the same: multiply every decimal price by the stake.
- Add an evens (2.0) shot to the double above: $10 × 3.5 × 2.5 × 2.0 = $175 (treble).
- Add a 4/5 (1.8) shot as well: $175 × 1.8 = $315 (four-fold acca).
Non-runners and void legs
If one selection is void, for example a non-runner, bookmakers usually treat that leg as odds of 1.0 and settle the rest. A $10 double with one void leg becomes a $10 single on the other selection. Check your bookmaker's rules for the exact treatment.
Why accumulators are harder than they look
Each price carries the bookmaker's margin, and multiplying prices multiplies the margin too. If every leg keeps about 95.2% of fair value, a four-fold keeps only about 0.952 × 0.952 × 0.952 × 0.952 ≈ 82%. Our bookmaker margin calculator guide shows where that figure comes from.
Each way singles in brief
An each way single is two bets: one to win, one to place at a fraction of the odds. $5 each way on a 10/1 horse at 1/4 odds costs $10.
- Wins: win part $5 × 11 = $55, place part at 10/4 (3.5) = $17.50. Total $72.50.
- Places only: $17.50, a $7.50 profit on the $10 outlay.
- Unplaced: you lose $10.
Each way doubles, Patents and the Lucky 15 build on this. See our free bet calculator guide for each way, Patent and Lucky 15 worked examples.
Singles with a free bet
A free bet usually returns only the profit, not the stake. A $10 free bet single at 5/2 returns $25, not $35. That's why free bets are worth more at slightly longer odds.
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