Parlay calculator
Free parlay calculator: type each leg's odds and your stake to see combined odds, payout, profit and the chance the whole bet actually wins.
Legs
3 legs- implied chance 55.6%
- implied chance 47.6%
- implied chance 60.6%
Your parlay
Combined odds6.2421/4 · +524
- Returns
- 62.37
- Profit
- 52.37
- Implied chance
- 16.0%
- Fair chance (est.)
- 13.9%
“Fair chance” strips a typical 5% bookmaker margin from each leg. It is an estimate, not a promise.
How the parlay calculator works
A parlay is one bet made of several picks, called legs. Every leg has to win. If one loses, the whole bet loses. In the UK the same bet is called an accumulator, or “acca”. Different word, same slip.
The calculator does what the bookmaker’s bet slip does, and then one thing the slip won’t. It turns each leg into decimal odds, multiplies them, and shows you the payout. Then it shows the chance those odds imply, which is the number that tells you what you’re really buying.
Pick the odds format you’re used to. Decimal (1.80), fractional (4/5) and American (−125) all work, and you can switch at any time without retyping.
The formula
Four lines cover it:
- Combined odds = leg 1 × leg 2 × leg 3… (in decimal odds)
- Payout = stake × combined odds
- Profit = payout − stake
- Implied chance = 1 ÷ combined odds
Fractional and American odds get converted first. 5/2 becomes 3.50 (5 ÷ 2 + 1). +150 becomes 2.50 (150 ÷ 100 + 1). −120 becomes 1.83 (100 ÷ 120 + 1).
A worked example
Say you like three football matches this weekend: a home win at 1.80, an away win at 2.10 and over 2.5 goals at 1.65. You stake 10.
- Combined odds: 1.80 × 2.10 × 1.65 = 6.237, shown as 6.24
- Payout: 10 × 6.237 = 62.37
- Profit: 62.37 − 10 = 52.37
- Implied chance: 1 ÷ 6.237 = 16.0%
So the bookmaker is telling you this bet lands about one time in six. On their own, those legs sit at 55.6%, 47.6% and 60.6%. Each one looks likely. Together they don’t, and that’s the whole trick of a parlay: three “probably” picks make one “probably not” bet.
Why every extra leg costs you
Bookmakers build a margin into every price. On a single bet you pay it once. On a parlay you pay it on every leg, and the margins multiply along with the odds.
Here’s what happens when every leg is a true coin flip priced at 1.91 (that’s −110, the usual American price on each side of a point spread or total):
| Legs | Combined odds | Chance you need to break even | True chance | Expected loss per 100 staked |
|---|---|---|---|---|
| 2 | 3.65 | 27.4% | 25.0% | 8.80 |
| 3 | 6.97 | 14.4% | 12.5% | 12.90 |
| 4 | 13.31 | 7.5% | 6.3% | 16.80 |
| 5 | 25.42 | 3.9% | 3.1% | 20.60 |
| 6 | 48.55 | 2.1% | 1.6% | 24.10 |
A single bet at those odds costs you about 4.50 per 100 staked. A six-leg parlay costs more than five times that. The payout looks bigger because the hole is deeper.
What “fair chance” means
The implied chance still has the bookmaker’s margin inside it, so it flatters the bet. The fair chance line assumes a 5% margin on every leg: it divides each leg’s implied chance by 1.05, which is the same as dividing the parlay’s implied chance by 1.05 once per leg. For the three-leg example above that’s 16.0% ÷ 1.05 ÷ 1.05 ÷ 1.05 = 13.9%.
It’s an estimate. Margins vary. One study of six large bookmakers put the average at about 4% on Premier League match odds and about 8% in England’s fifth tier, and niche markets can carry more. I can’t see the margin on your slip, so 5% is a round middle figure. Treat the figure as a reality check, not a forecast.
When I’d use a parlay
Rarely, and for small stakes. A parlay makes sense when you’d happily back each leg on its own, and you accept that you’re trading a lower chance of winning for a bigger payout. It makes no sense as a way to turn weak picks into a strong bet. Multiplying doesn’t fix a bad price. It compounds it.
Bet only what you can afford to lose. 18+.
Parlay calculator: questions
How do I calculate parlay odds by hand?
Turn every leg into decimal odds and multiply them. Three legs at 1.80, 2.10 and 1.65 make 1.80 × 2.10 × 1.65 = 6.24. Multiply that by your stake to get the payout, then take the stake off to get the profit.
Is a parlay the same as an accumulator?
Yes. Parlay is the American word, accumulator (or acca) is the British one, and some bookmakers call it a multi or a combo bet. It's the same thing: several picks on one slip, and every one of them has to win.
What happens if one leg is void or a push?
On a standard parlay, bookmakers normally settle a void or pushed leg at odds of 1.00, so the bet carries on with the legs that are left. Remove that leg here to see the new payout. Check your bookmaker's rules: same-game parlays (bet builders) are the usual exception, and some bookmakers void the whole bet when one of those legs is void.
How many legs can I add?
From 2 to 15. Bookmakers set their own limits, and some allow more, but the maths tells you to stop long before that: a six-leg parlay of coin-flip picks wins once in 64 tries on average.
Does the calculator store or send my numbers?
No. It runs in your browser. Nothing you type is saved, and nothing is sent to me or to anyone else. There's no account and no sign-up.