Dutching and the book percentage
Dutching is backing several selections in one market with stakes sized so that each returns the same amount if it wins. Whether the whole set makes or loses money is decided by one number, the book percentage. This lesson shows the arithmetic and its limits.
Suppose you think a race will be won by one of three horses, priced at 3.50, 4.20 and 6.00, and you do not mind which. You could back all three for the same stake, but then your profit depends on which one wins. Dutching sizes the three stakes so that the return is the same whichever of them wins. It is a way of turning a view about a group of selections into one bet.
The book percentage
First, add up the implied chances of your selections: 100 / 3.50 + 100 / 4.20 + 100 / 6.00 = 28.6% + 23.8% + 16.7% = 69.0%. That total is the book percentage of your set. It tells you how much of the total stake comes back if one of them wins:
Return = total stake / (book percentage / 100)
With ₹1,000 across the three: return = ₹1,000 / 0.690 = ₹1,449, a profit of ₹449 if any of the three wins. If the book percentage were over 100%, the return would be less than the stake, so dutching those selections could only lose.
Sizing the stakes
Each selection gets a share of the total in proportion to its implied chance:
Stake on a selection = total x (1 / its odds) / sum of (1 / odds)
- 3.50: ₹1,000 x 0.2857 / 0.690 = ₹414
- 4.20: ₹1,000 x 0.2381 / 0.690 = ₹345
- 6.00: ₹1,000 x 0.1667 / 0.690 = ₹241
Check: ₹414 x 3.50 = ₹1,449; ₹345 x 4.20 = ₹1,449; ₹241 x 6.00 = ₹1,449. The dutching calculator does this for any number of selections and shows the profit after commission.
What dutching does not do
- It does not cover everything. If a fourth horse wins, all three stakes are lost. Covering the whole field at exchange prices gives a book over 100% and a guaranteed loss.
- It does not improve the prices. You are still backing each selection at its market price; dutching only shapes the payout.
- It needs matching. Three bets must all be matched at the planned prices, which in a moving market may not happen.
Where the idea comes from
The same arithmetic, run in reverse, is how a bookmaker builds a book: it chooses prices whose implied chances add up to more than 100% so that, if its stakes are spread in proportion, it keeps the difference whichever selection wins. Understanding dutching is understanding the bookmaker's margin from the other side. Next: trading a position.
Information only, 18+. Nothing here says which selections to back. Real-money online gaming is restricted in India: see the lesson on the law.
How the Horse racing markets are read
18+ only. This lesson is for information, not advice to bet. Responsible gambling.