Rule 4 Deduction Calculator
⚠ If multiple non-runners apply, deductions are combined but cannot exceed 75p in the £ total.
What is a Rule 4 deduction?
A Rule 4 deduction is a reduction applied to your winnings when a horse is withdrawn from a race after you have already placed your bet. Because the non-runner made the remaining field more likely to win, your odds were effectively too generous — Rule 4 corrects for this by deducting a percentage of your profit. The size of the deduction depends on how short-priced the non-runner was at the time of withdrawal: a 2/1 favourite withdrawn causes a bigger reduction than a 12/1 outsider.
When does Rule 4 apply?
Rule 4 applies when a horse is declared a non-runner after bets have been placed but before the race is run. This includes horses withdrawn on race day due to veterinary advice, weather, ground conditions or jockey injury. It also applies to ante-post bets where the race card changes after your bet was struck — although many ante-post markets are offered on a "non-runner no-bet" basis, in which case no deduction applies and your stake is simply returned. Always check the terms of your bet before placing ante-post.
Rule 4 deduction table
| Non-runner SP | Deduction (p in the £) | % of profit deducted |
|---|---|---|
| 3/10 or shorter | 75p | 75% |
| 1/3 to 2/5 | 70p | 70% |
| 8/15 to 4/9 | 65p | 65% |
| 4/6 to 8/13 | 60p | 60% |
| 8/11 to 4/7 | 55p | 55% |
| 4/5 to 5/6 | 50p | 50% |
| Evens to 6/5 | 45p | 45% |
| 5/4 to 6/4 | 40p | 40% |
| 13/8 to 7/4 | 35p | 35% |
| 15/8 to 9/4 | 30p | 30% |
| 5/2 to 3/1 | 25p | 25% |
| 10/3 to 4/1 | 20p | 20% |
| 9/2 to 11/2 | 15p | 15% |
| 6/1 to 9/1 | 10p | 10% |
| 10/1 to 14/1 | 5p | 5% |
| 14/1 or longer | None | 0% |
Rule 4 deductions in multiples
If a non-runner affects a leg of an accumulator, patent or Lucky 15, the Rule 4 deduction is applied to that leg's return before it rolls into the next leg. For example, in a treble where leg one wins at 4.0 odds subject to a 20p Rule 4 deduction, the adjusted odds for that leg become 4.0 − (3.0 × 0.20) = 3.40. That adjusted figure then multiplies through the rest of the bet. For multiples with many legs, deductions can compound significantly — always check the settled return carefully rather than relying on the pre-race estimate.
How to avoid Rule 4 deductions
Some Irish bookmakers offer a non-runner no-bet guarantee on selected races — if a horse is withdrawn, your stake is returned rather than a deduction being applied. Others offer ante-post NR insurance as a promotion around major festivals such as Cheltenham or the Galway Races. If you are placing a bet on a race where late withdrawals are common (large fields, soft ground, festival racing), it is worth checking whether these offers are available. Using the calculator above, you can quickly see how much a Rule 4 would cost on any given bet before you decide to take it.
Frequently Asked Questions
A reduction applied to winnings when a horse is withdrawn from a race after bets have been placed. The deduction reflects the removed horse's starting price and is applied to all bets already struck on that race.
From 5p in the £ for outsiders (10/1–14/1) up to 75p in the £ for very short-priced favourites (3/10 or shorter). No deduction applies at 14/1 or longer.
Yes — the deduction applies to both the win and place parts of an each-way bet.
Yes — if more than one horse is withdrawn, deductions are added together, but the total cannot exceed 75p in the £.
Ante-post bets are often "non-runner no-bet" so no deduction applies — your stake is returned instead. Always check your bookmaker's terms when placing ante-post bets.