This dutching calculator turns 2 to 10 decimal prices and a total stake or target return into the stake for each selection, so the same amount comes back whichever of them wins. It answers with the stake on each selection, what that selection pays, the profit if one of them wins and the book percentage those prices add to. A selection you leave out is not covered: if it wins, every stake is lost.
How betting odds work covers the chances those prices imply, and dutching explained covers when to spread a stake at all.
How to use the dutching calculator
Four inputs, plus a price box per selection.
- Size it by: Total stake, or Target return.
- Total stake or Target return: the amount, $0.01 to $1,000,000.
- Commission %: 0 at a bookmaker, or your exchange account's rate when every leg is backed on the exchange.
- Round stakes to: Cents, 10c, 50c or $1. Pick the smallest unit your bet slip accepts.
- Selection 1 to 10 odds: decimal prices, $1.01 to $10,001. Three boxes open with a market already typed in; Add a selection gives another, up to 10, Remove takes one away, down to two, and a blank box leaves that selection out.
A fraction such as 5/2, a decimal comma, one price on its own or commission of 100% or more gives no answer until it is fixed.
Four tiles follow: the book percentage, the outlay, the equal return and the least profit if one lands. Every selection then gets its own row, so the result that pays least is visible, and a last row shows the whole outlay lost if anything else wins.
The dutching formula
Each line uses the one before it.
- implied probability of a selection = 1 / decimal odds
- book percentage = those implied probabilities added up across the selections you back
- equal return = total stake / book percentage
- stake on a selection = equal return / that selection's decimal odds
- profit if one of them wins = equal return - total stake
Read backwards it gives the target return mode: total stake = return x book percentage.
A worked dutch on three selections
With illustrative prices of $2.75, $4.50 and $7.00 and an $80 total stake:
| Step | Working | Result |
|---|---|---|
| The three chances, added | 1 / 2.75 + 1 / 4.50 + 1 / 7.00 | a 72.9% book |
| Equal return | 80 / 0.728716 | $109.78 |
| The three stakes | 109.782 / 2.75, / 4.50, / 7.00 | $39.92, $24.40, $15.68 |
| Outlay, then the return | 39.92 + 24.40 + 15.68, then 39.92 x 2.75 | $80.00, then $109.78 |
| Profit | 109.78 - 80.00 | $29.78 |
That profit is 29.78 / 80.00 = about 37.2% of the outlay, which is 1 / 0.728716 - 1. Rounding to the cent leaves the three legs paying $109.78, $109.80 and $109.76, so the least of them is the figure to judge on.
Risk: Betting involves risk. Those three prices add to a 72.9% book, which includes the bookmaker's margin and so is not the chance one of them wins: the position only breaks even if one of the three wins at least 72.9% of the time. If any other runner wins, the whole $80.00 is lost. See responsible gambling for limits and support.
What the book percentage tells you
The book percentage covers only the selections you typed. Under 100% it says the runners you backed pay back more than they cost between them, and nothing about the ones you left out. If the boxes hold every outcome of the market and the prices still add to under 100%, which usually takes a price from more than one bookmaker, the same split is an arbitrage: how arbitrage betting works covers that case, and the arbitrage calculator runs the split on a complete market. Even then every bet has to be accepted at the price shown.
As a test it is a question about implied probability: break-even sits where the real chance one of your selections wins equals the book percentage.
Where the book is above 100%, as a whole field at one bookmaker is by its margin, every result loses: on illustrative prices adding to a 111.0% book, $500 over ten runners returns about 500 / 1.110 = $450 whichever wins, a loss of about $50.
Why rounding makes the returns uneven
A bet slip takes whole units, so a rounded stake no longer pays the equal return. With illustrative prices of $2.00, $4.00 and $8.00 on a $50 stake, the book is 87.5% and the equal return is 50 / 0.875 = $57.14:
| Round to | Stakes | Returns | Worst profit | Best profit |
|---|---|---|---|---|
| Cents | $28.57, $14.29, $7.14 | $57.14, $57.16, $57.12 | +$7.12 | +$7.16 |
| $1 | $29, $14, $7 | $58, $56, $56 | +$6.00 | +$8.00 |
Both outlays come to $50.00, so the whole spread is rounding. Dollar units on a thin book can put one result under the outlay and another over it, which is why the least of those profits is the figure to judge on. A long price can also round away to nothing, leaving that selection uncovered, which the calculator flags.
Commission on an exchange dutch
Where every leg is backed in the one exchange market, the exchange charges commission on what that market nets: the losing stakes come off first. The base is the payout less the whole outlay, not the winning selection's own winnings, and that is what the Commission box applies.
profit after commission = (equal return - outlay) x (1 - commission rate), when that is a profit; a result that loses money pays no commission
With illustrative prices of $2.00 and $4.00, a $100 stake and an illustrative 5% rate, the stakes are $66.67 and $33.33 and each returns about $133.33. Taking 5% off the exact gross profit, (133.333 - 100) x 0.95, leaves about $31.67, and with the stakes rounded to the cent the two legs show $31.67 and $31.65. The stakes do not move, because every leg's gross profit is the same number and the rate scales them alike. Rates differ by account, so the box opens at 0, and exchange commission covers how the charge is worked out.
The box assumes every leg sits in that one exchange market. Put the $2.00 at a bookmaker instead and commission falls only on the exchange leg, which nets 33.33 x 3 x 0.95 - 66.67 = $28.32 against the bookmaker leg's $33.34, so the split does change. For a mixed position, leave the box at 0 and type the exchange leg's price after commission, 1 + (4.00 - 1) x 0.95 = $3.85.
Dead heats, and a late scratching
Where a betting rule book covers it, a dead heat divides the return by the number of runners tying for the paid place. The Racing NSW Rules of Betting, which cover NSW on-course bookmakers, betting auditoriums and betting premises, pay half the ticket's face value for a dead heat for first (BR 16). On the worked example each leg's $109.78 becomes about $54.89: two of your own selections tying pays it twice, so the profit is still about $29.79, while a tie with an uncovered runner pays it once and loses about $25.11. Online bookmakers set their own dead heat terms, so check them; dead heat rules sets out how each rule book splits the return.
A late scratching also moves the numbers: money on the scratched runner is refunded, and successful fixed-odds bets placed before it are paid less a deduction in cents in the dollar set by the stewards. How a bookmaker applies that deduction is set out in its terms, so check them. If the scratched runner is one you left out, nothing comes back and your winner is still cut, so a thin dutch can finish behind. Scratchings and deductions covers how it is applied.
Mistakes that cost money
With the illustrative $80 over $2.75, $4.50 and $7.00:
| Mistake | What it costs | The fix |
|---|---|---|
| Staking the same amount on each | $26.67 each returns $73.34, $120.02 or $186.69 on an $80.01 outlay, so the shortest price loses $6.67 | Stake equal return / odds |
| Reading the equal return as the profit | $109.78 back on $80.00 is $29.78 of profit, not $109.78 | Take the outlay off the return |
| Adding a selection and leaving the stakes | A fourth price raises the book, so every stake already worked out is wrong | Re-run the whole split |
Comparing each selection's price across bookmakers
The best price for each runner is often at a different bookmaker. The Terminal shows prices from 40+ bookmakers across racing and sports, beside Betfair back and lay. A free account opens a limited view of the Terminal with live odds. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
Risk: Betting involves risk. Prices are read on a repeating cycle, so one on screen can trail the bookmaker's own: confirm it before you bet. The split only holds if every leg is accepted at the price you typed in, and many bookmakers restrict automated betting, third-party access or multiple accounts and can limit your stakes, void a bet or close your account under their terms. See responsible gambling for limits and support.