Rule 4 deductions often have a negative association for horse racing bettors, because at the moment we first need to ask what a rule 4 is, more often than not it has often just cost us money.
A rule 4 deduction is needed to keep horse racing betting fair. In fact, it is much more favourable to punters than most similar rules, but we will come back to that.
A rule 4 is essentially a deduction from winnings which needs to be applied after a non-runner is declared. It is an attempt to make the market fair again, because when one horse is made a non-runner the chances of all the remaining horses will obviously increase.
Rule 4 deductions can apply to bets placed at the starting price (SP), but can also be necessary on bets where a punter has taken a ‘fixed’ price.
How To Calculate Rule 4 Deductions
Rule 4 deductions are calculated using the price of the withdrawn horse or horses at the time they were declared a non-runner. The shorter the horse’s price, the greater chance it was deemed to have and the greater the rule 4 deduction will need to be.
The best way to calculate rule 4 deductions is by using the table below. As a rule of thumb, you will not lose more from your winnings than the withdrawn horse was taking up in the betting. So for instance, you might expect the rule 4 deduction on an even-money shot to be 50p in the pound. The deduction is in fact just 45p.
Just remember that the rule 4 deduction is always determined by the price of the withdrawn horse, not the price of your selection.
Rule 4 Deductions Table
| Price at withdrawal | Decimals | Deduction (p/£) |
| 1/9 or shorter | 1.11 or shorter | 90p |
| 2/11 to 2/17 | 1.18 to 1.12 | 85p |
| 1/4 to 1/5 | 1.25 to 1.20 | 80p |
| 3/10 to 2/7 | 1.30 to 1.29 | 75p |
| 2/5 to 1/3 | 1.40 to 1.33 | 70p |
| 8/15 to 4/9 | 1.53 to 1.45 | 65p |
| 8/13 to 4/7 | 1.62 to 1.57 | 60p |
| 4/5 to 4/6 | 1.80 to 1.66 | 55p |
| 20/21 to 5/6 | 1.95 to 1.83 | 50p |
| Evens to 6/5 | 2.00 to 2.20 | 45p |
| 5/4 to 6/4 | 2.25 to 2.50 | 40p |
| 8/5 to 7/4 | 2.60 to 2.75 | 35p |
| 9/5 to 9/4 | 2.80 to 3.25 | 30p |
| 12/5 to 3/1 | 3.40 to 4.00 | 25p |
| 16/5 to 4/1 | 4.20 to 5.00 | 20p |
| 9/2 to 11/2 | 5.50 to 6.50 | 15p |
| 6/1 to 9/1 | 7.00 to 10.00 | 10p |
| 10/1 to 14/1 | 11.00 to 15.00 | 5p* |
| Over 14/1 | Over 15.00 | No deduction |
* Not all bookmakers will apply a 5p Rule 4 deduction, and some have specific rules around 5p deductions. Please check with individual bookmakers.
Rule 4 In Horse Racing
In the days when most betting was done at SP, rule 4s were mostly used when a horse was withdrawn so close to a race starting that a new market could not be formed. Nowadays, it is more common to see rule 4s on bets placed well before the race, as fewer punters are betting at SP.
Note that rule 4 deductions do not apply to ante-post bets, as stakes are not refunded on the withdrawn horse. Rule 4 deductions apply equally on Flat and National Hunt racing.
Bookmakers That Offer Rule 4
All bookmakers in the UK and Ireland abide by the rule 4 guidelines. The only exception is those who offer a bit of leeway with 5p deductions.
Ladbrokes were among the first firms to waive 5p rule 4 deductions, with fellow retail giants William Hill and Coral close behind. All three firms still waive 5p rule 4s, but only in the first instance. So if one horse at 10-1 is withdrawn, there is no deduction but if a second horse priced at 10-1 is withdrawn then a 5p rule 4 is triggered. This is still better than the 10p deduction that would otherwise have been triggered.
The only major UK bookmaker who disregards all 5p rule 4 deductions is bet365.
If your bet is subject to a rule 4 deduction and you placed it online, most firms will point this out wherever you can see the settled bet.
More Than One Rule 4 In A Race
In some cases, more than one horse will come out of a race between your bet being placed and the off-time. In these cases, rule 4 deductions will add up and can quickly eat into your winnings.
The calculation is quite simple. A horse at 4-1 is withdrawn, triggering a 20p rule 4, and later one at 6/1 is withdrawn to trigger a 10p rule 4. The total deduction will be 30p per £1.
Note that the total rule 4 deduction can never exceed 90p per £1.
How To Work Out How Much a Rule 4 Will Cost Me
Working out the deduction from a bet affected by a rule 4 is fairly simple. The only thing to remember is that deductions are only taken from any winnings, and your initial stake will be left untouched.
Imagine you have placed a bet with a £10 stake on a horse priced at 10-1. Your horse wins, but there is a 5p rule 4 reduction applied to your bet. Without the rule 4, your returns would be £110. In this case your winnings would be £100, i.e. your returns minus your stake.
The rule 4 deduction is calculated by applying the reduction to the winnings only. In this case, that would be 5p x 100, or £5. So your returns will be £5 less than £110, i.e. £105.