This multi bet calculator multiplies the decimal odds of every leg together and works out what your stake returns at that combined price, void and dead heat legs included. A parlay is the American word for the same bet, so a parlay calculator in Australia is this arithmetic in decimal odds.
Each betting leg's price multiplies the rest, so one void or tied leg changes the whole return, not just its own.
How to use the multi bet calculator
Six inputs, live as you type:
- Stake type: cash, or a bonus bet whose stake is not returned.
- Stake: $0.01 to $1,000,000.
- Leg odds: $1.01 to $10,001 on each of two to ten legs. A blank box drops that leg out.
- Leg result: won, lost, void or dead heat.
- Runners tied: on a dead heat, how many tied for one paying place: 2 for a head to head draw, or a tie for the last paying place.
- Market margin: optional, the market's percentage over 100, so 5 for a 105% book.
The tiles read combined odds, returns, profit (Cash profit on a bonus bet), combined margin and fair combined odds; the leg table's last Price after this leg figure is what the bet paid. Prices round to two places for display: two illustrative $1.15 legs show $1.32, but the unrounded product returns $132.25 on $100.
How to calculate multi odds
A multi rides each leg's whole return onto the next, so the prices multiply rather than add:
- combined odds = leg 1 odds x leg 2 odds x ... x leg n odds
- return = stake x combined odds
- profit = return - stake
Example: Illustrative prices. Three legs at $1.80, $1.90 and $2.00: 1.80 x 1.90 x 2.00 = 6.84, so $10 returns $68.40 for $58.40 profit.
Adding the prices instead gives 5.70, and $68.40 is the return, not the profit. The implied chance is 1 / 6.84, about 14.6%.
Void legs, dead heats and a leg that loses
Three results are not the leg's price:
- Void: the leg settles at 1.00, so the multi reprices on what remains, and every leg void refunds a cash stake in full.
- Dead heat: the price is divided by the number tied, which on a cash bet is the same as splitting the stake between them at full odds, so a short leg lands below 1.00 (1.80 / 2 = 0.90).
- Lost: the leg multiplies by 0.
With those legs and $10 on the bet:
| What happened | Settled price | $10 returns |
|---|---|---|
| Leg 3 void | 3.42 | $34.20 |
| Leg 1 dead heat, two tied | 3.42 | $34.20 |
The Combined odds tile still reads $6.84 on the tied row: it is the price if every leg still in the bet wins, so only a void leg changes it.
Whose dead heat rule this is
Dividing by the number tied is not a national standard, and each book writes its own terms, so check yours. The Bookmaker Declared Betting Events Betting Rules, for declared events with NSW-authorised bookmakers (checked October 2026), divide a tied leg's face value by the number tied and multiply by the places to be filled, leg by leg inside a multi (5.1.8, 5.1.9); where a draw price was offered, other bets lose (5.1.7). WA's Rules of Wagering divide by the number tied too (r 58), while Racing NSW's on-course rule pays half the ticket's face value for a tie for first or the last paying place (BR 16), the same as dividing by the number tied when two tie.
This calculator assumes one place: a drawn AFL head to head goes in as Dead heat with 2 tied, or Void where your bookmaker voids it (AFL draw rules). Where the tied runners fill more than one place it does not apply: the rule pays price x places / number tied, so two tied for 2nd in a top-3 market go in as won. There is no deduction box either: price a leg cut by a late scratching in the scratching deductions calculator and type that in as its odds.
What a bonus bet multi pays
A stake-not-returned bonus bet pays the winnings and keeps the stake:
- bonus bet return = bonus stake x (combined odds - 1)
Example: Illustrative numbers. A $10 bonus bet at the combined $6.84 pays 10 x (6.84 - 1) = $58.40, against $68.40 for a $10 cash bet.
The bonus stake is not your cash and does not come back, so the tool counts the whole payout as profit. Every leg void pays nothing, as there is no stake to refund. A dead heat is where two readings part: dividing the price, as this calculator does, pays 10 x (3.42 - 1) = $24.20 on the tied $1.80 leg, while half the stake at full odds pays 5 x (6.84 - 1) = $29.20. Only the divided price can pay nothing, so check your terms.
Risk: Betting involves risk. A bonus bet that loses pays nothing, and the bookmaker's terms decide how it works. See responsible gambling for limits and support.
Reading the combined margin and fair price
With a margin on every leg in the bet, the Combined margin tile multiplies their books and Fair combined odds takes it out:
- combined book = leg 1 book x leg 2 book x ... x leg n book
- fair combined odds = combined odds x combined book
Example: Illustrative books of 104%, 105% and 106%: 1.04 x 1.05 x 1.06 = 1.15752, so the tile reads 15.8% where no leg carried more than 6%, and the fair price is 6.84 x 1.15752 = $7.92.
That fair price spreads each margin in proportion. A void leg takes its market out with it, and a leg with no margin leaves both tiles reading Not entered.
What the calculator refuses
It shows nothing rather than a wrong answer for:
- a price under $1.01 or over $10,001, or a combined price past $1,000,000,000
- fewer than two priced legs, or more than ten
- a stake outside $0.01 to $1,000,000, or a decimal comma such as 2,50
- a dead heat with one runner tied or more than 20, or a margin of 100% or more
Nor a same game multi: those legs move together, so the bookmaker prices the combination and the product usually overstates it (how same game multi odds are calculated).
Comparing a leg's price before you bet
The Terminal shows prices from 40+ bookmakers across racing and sports, beside Betfair back and lay, with price history, so you can compare a leg's price on the markets it carries. Not every bookmaker prices every race or game, so the columns follow the market, and prices are read on a repeating cycle: confirm each leg in your own account first. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
Risk: Betting involves risk. A multi loses more often than a single because every leg has to land, and a bookmaker can void legs or limit stakes. See responsible gambling for limits and support.