How is a Rule 4 deduction calculated?
Rule 4 normally reduces the profit from a winning fixed-price bet after a relevant non-runner is withdrawn. The returned stake is kept separate. Multiply the original profit by the deduction rate, subtract that amount from the profit, then add the stake back.
| Step | Calculation |
|---|---|
| Original profit | Stake × fractional odds |
| Deduction | Original profit × deduction pence ÷ 100 |
| Adjusted return | Stake + original profit − deduction |
Worked example: £10 at 4/1 with a 20p deduction
A £10 win bet at 4/1 makes £40 profit before the deduction. Rule 4 removes 20% of that profit, which is £8. The adjusted return is therefore £42: the £10 returned stake plus £32 adjusted profit.
| Stake | Price | Original profit | Deduction | Adjusted return |
|---|---|---|---|---|
| £10.00 | 4/1 | £40.00 | £8.00 | £42.00 |
Standard Rule 4 deduction table
The deduction is linked to the withdrawn horse's price at the reference time stated in the operator's rule. That may be the market when the bet was placed or the price when the withdrawal became official. A shorter-priced non-runner has a larger effect on the remaining market, so it produces a larger standard deduction.
| Price of withdrawn horse | Deduction per £1 profit |
|---|---|
| 1/9 or shorter | 90p |
| 2/11 to 2/17 | 85p |
| 1/4 to 1/5 | 80p |
| 3/10 to 2/7 | 75p |
| 2/5 to 1/3 | 70p |
| 8/15 to 4/9 | 65p |
| 8/13 to 4/7 | 60p |
| 4/5 to 4/6 | 55p |
| 20/21 to 5/6 | 50p |
| Evens to 6/5 | 45p |
| 5/4 to 6/4 | 40p |
| 8/5 to 7/4 | 35p |
| 9/5 to 9/4 | 30p |
| 12/5 to 3/1 | 25p |
| 16/5 to 4/1 | 20p |
| 9/2 to 11/2 | 15p |
| 6/1 to 9/1 | 10p |
| 10/1 to 14/1 | 5p |
| Over 14/1 | No deduction |
When Rule 4 may not apply in the same way
Ante-post bets commonly use all-in, run-or-not terms. Bets placed after a market has been reformed already use prices formed without the earlier withdrawal. Each-way bets have separate win and place profit calculations, and operator-specific concessions can change the final deduction.
For an each-way bet, first use the each-way calculator to separate the two returns. Then check the operator's published rule and the deduction shown on the settled bet. The calculator reproduces the arithmetic; it cannot decide whether a bookmaker applied its terms correctly.