Rule 4 Explained: How Rule 4 Deductions Work
Rule 4 deductions adjust winning bets if a runner withdraws from a race after bets are placed.
Read on to learn how Rule 4 deductions work and how they can affect your payouts.
Note: This guide references fractional odds (e.g., 4/1) and British currency (GBP). The same principles apply globally—adjust for your local odds format (decimal or American) and currency.
How Rule 4 Affects Payouts
Rule 4 protects betting sites when any horse but a longshot drops out of a race. In particular, it is applied when a horse priced 14/1 or shorter is withdrawn from a race.
The shorter the odds of the withdrawn horse, the larger the Rule 4 deduction from any winning bets.
So, if a horse priced at 2/1 withdraws at the start of a race, a significant Rule 4 deduction would apply. In this instance, winning bets would be adjusted by 30%, or 30p to £1.
If you had bet £10 on the 4/1 winner, instead of winning £40, your profits would be adjusted to £28 (plus your £10 stake), because the R4 deduction of 30% would equate to a £12 adjustment.
However, if the odds of a withdrawn horse are greater than 14/1, no Rule 4 deduction is applied to the winning bets placed after the withdrawal. So, if a 20/1 contender drops out, there will be no deduction to winning bets.
Are There Minimum & Maximum Rule 4 Deductions?
Yes, there are minimum and maximum deductions for Rule 4 in horse racing.
The trigger price for a Rule 4 deduction is 14/1, which results in a 5p in the £1 deduction. Any withdrawal priced greater than 14/1 would not initiate a Rule 4, even if there were multiple withdrawals at those higher odds.
From that point, the shorter the odds, the bigger the deduction, right up to 1/9 or shorter, which triggers the maximum 90p per £1 maximum Rule 4 deduction.
The maximum 90p in the £1 Rule 4 deduction wipes out most profits on a winning bet, but such drastic deductions are rare.
For example, £500 in winnings would be reduced to just £50 if there were a 90% deduction.
Can You Have Multiple Rule 4 Deductions in One Race?
Yes. Rule 4 deductions are applied to each withdrawn horse in a race, provided their odds are 14/1 or shorter at withdrawal time.
In the case of multiple Rule 4 deductions, the cumulative total is deducted from any winnings.
So, if two horses are withdrawn from a race after placing your bet, and the individual R4 deductions are 15p and 35p, then a total of 50p will be deducted from every £1 of your winnings.
Although uncommon, two or three horses could be withdrawn right before the race starts, especially if trouble there's trouble in the starting stalls.
Three withdrawals at odds of 8/1, 10/1, and 12/1 would result in a total of 20p in the £1 Rule 4 deduction (10p + 5p +5p).
How Rule 4 Deductions Are Calculated
Rule 4 deductions are uniform across the betting industry, which means horse racing betting sites apply the same adjustments in the event of a non-runner.
The table below outlines the industry standard reductions applied to each price range. It shows that a horse priced 7/2 (falling between 10/3 and 4/1) would generate a 20p Rule 4 deduction at withdrawal time.
| Odds Of Withdrawn Horse | Deduction (per £ winnings) |
|---|---|
| 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 |
| 13/8 to 7/4 | 35p |
| 15/8 to 9/4 | 30p |
| 5/2 to 3/1 | 25p |
| 10/3 to 4/1 | 20p |
| 9/2 to 11/2 | 15p |
| 6/1 to 9/1 | 10p |
| 10/1 to 14/1 | 5p |
| 15/1 and upwards | No deduction |
So, any bets on the race winner before that horse’s withdrawal will have their winnings subjected to a 20% adjustment.
If you had £50 on the even money winner, instead of having £100 returned, you'd get £90 as you'd lose £10 (20p in the £1 of winnings).
More than one Rule 4 deduction can be applied if multiple horses are withdrawn from a race, with the maximum deduction on a single runner being 90p per £1.
When Are Rule 4 Deductions Applied?
A Rule 4 deduction kicks in when a horse is withdrawn from a race.
Any bets placed after final declarations but before a horse is withdrawn will automatically be subject to a Rule 4 deduction.
Any adjustments to returns due to non-runners are made at the point of payout, meaning your winnings will already reflect any Rule 4 deductions.
How Does Rule 4 Affect Each-Way Bets?
Rule 4 deductions apply to the win and place parts of an each-way bet if they concern the horse that went on to win.
A 30p Rule 4, for example, could be deducted from win and place returns.
If the each-way wager yields only a place return, then the R4 deduction would be applied to that alone.
Does Rule 4 Affect Ante-Post Bets?
Rule 4 deductions do not apply to ante-post bets. Thanks to the longer timeframes involved in the lead-up to major racing festivals and events, horses regularly drop from ante-post betting lists due to injury, form, change of targets, etc.
This scenario changes, however, from the moment final declarations—when the official list of runners is confirmed—are made for a race. Any bets placed after this point, where a new market is formed, will be subject to a Rule 4 deduction should a qualifying horse be withdrawn.
