Rule 4 Deductions Explained: The Full Table and Worked Examples

Rule 4 exists because of one awkward fact about horse racing: the field can change after you have placed your bet. If a runner is taken out of a race close to the start, every other horse has one fewer rival, and the prices struck before the withdrawal were set for a harder race. Rule 4 deductions are how the betting rules put that right.

They catch a lot of people out because they turn up only on the day something goes wrong. The horse wins, the price looked fixed, and the return is smaller than the sum on the back of the slip.

What Rule 4 deductions are

The rule comes from the Tattersalls Committee’s rules on betting, which British bookmakers work under. When a horse is withdrawn and there is not enough time to form a new betting market without it, bets already struck at a fixed price on the other runners are settled with a deduction from the winnings.

Three points define it. The deduction comes off the winnings, never the stake. It depends on the price of the withdrawn horse when it came out, so a favourite pulling out costs far more than an outsider. And it only applies to bets struck before the withdrawal. A bet placed after a new market has formed without that horse is settled at its price in full.

The logic is easy to see with an extreme case. If a 1/5 favourite is withdrawn from a three-runner race, the horse that was 5/1 second favourite has become the likely winner. Paying it at 5/1 would be paying a price set for a race that no longer exists. A deduction of 80p in the pound brings the winnings back towards something fair.

The Rule 4 deductions table

The deduction is read off a fixed scale according to the withdrawn horse’s price:

A deduction is often written in shorthand, such as “R4 20p”, meaning 20p in the pound. It is the figure in the right-hand column that goes into the sum.

Why the table looks the way it does

The scale is not arbitrary, and seeing why makes it easier to remember. Each deduction is close to the chance implied by the longest price in its band. A 4/1 shot implies a 20% chance and costs 20p. A 3/1 shot implies 25% and costs 25p. A 6/4 shot implies 40% and costs 40p. At the short end, a 1/9 shot implies a 90% chance and costs 90p.

In other words, Rule 4 takes away roughly the share of the race the withdrawn horse was expected to win. If a horse the market gave a one-in-four chance leaves the race, the others share its chance between them, and a quarter of your winnings comes off to reflect that. The bands step in 5p units, so the deduction is a rounded version of that idea rather than an exact one.

It also explains why an outsider costs nothing. A horse longer than 14/1 had a small implied chance, and removing it barely changes the race for the rest.

Rule 4 worked through

Take a £20 win bet at 7/2. The horse wins. Without any withdrawal, the winnings are £70 and the bet returns £90.

Now suppose a 6/4 shot was withdrawn after you struck the bet, too late for a new market. The table gives 40p. Forty per cent of the £70 winnings comes off, leaving £42, and the £20 stake comes back on top. The bet returns £62 instead of £90. The calculator at the bottom of this page is loaded with exactly this bet.

The size of the withdrawn horse’s price matters enormously. The same £10 win bet at 2/1 returns £29 when the withdrawn horse was a 12/1 chance, a 5p deduction, and only £12 when it was a 1/10 shot, a 90p deduction. The second case shows what the rule is for: when the horse that was expected to win disappears, the price on the rest was badly wrong.

If two horses are withdrawn, the deductions are combined, up to a ceiling set in the rules. A 4/1 withdrawal (20p) and an 8/1 withdrawal (10p) make 30p between them, and £10 on a 4/1 winner then returns £38. Each deduction only touches bets struck before that particular horse came out, so a bet placed between the two withdrawals takes only the second deduction.

Rule 4 on each way bets

Each way bets take the deduction on both halves. The reduced price is worked out first, and the place part is then calculated from it.

Take £5 each way at 12/1 in a race paying 1/5 of the odds, and a 5/1 horse withdrawn late, which means a 15p deduction. The 12/1 is cut by 15%, which leaves 10.2 to 1. A fifth of that is 2.04 to 1 for the place. If your horse places, the place half returns £15.20. If it wins, the win half adds £56.00, for £71.20 in all.

A withdrawal can also change the each way terms themselves, because the places paid depend on the number of runners that actually start. That is a separate effect from the deduction and is covered in the each way guide.

Rule 4 in doubles and accumulators

In a multiple, Rule 4 only affects the leg in the race where the withdrawal happened. The reduced price is carried into the multiple, and the other legs stand at their own prices.

A £10 double on a 7/2 winner with a 40p deduction and a 2/1 winner in a different race: the 7/2 becomes 2.1 to 1 after the deduction, so 3.1 in decimals, and the double pays £10 × 3.1 × 3.0 = £93. Without the withdrawal it would have paid £135. The bet calculator handles Rule 4 on any leg of any multiple.

When Rule 4 deductions don’t apply

Several kinds of bet sit outside the rule.

Bets at the starting price. After a withdrawal, the market re-forms and the SP already reflects the smaller field, so SP bets are normally settled without a deduction. The exception is a withdrawal so late that no new market can be formed, and then SP bets can be affected too. The starting price page explains how the SP is compiled.

Ante-post bets. Bets struck before the final declarations are not subject to Rule 4. The trade-off is harsh: if your own horse doesn’t run, the stake is normally lost. The ante-post guide covers it in full.

Bets struck after the new market. Once the market has re-formed without the withdrawn horse, new bets are struck at the new prices and carry no deduction.

Tote bets. The tote has its own rules for withdrawals, and its dividends are worked out from the pool rather than a fixed price.

Dead heat rules

Dead heats are the other common reason a winner pays less than expected, and they are often confused with Rule 4. They are quite different. Rule 4 cuts the price. The dead heat rules cut the stake.

When two or more horses cannot be separated for a position, the stake is divided by the number of horses sharing it, and the divided stake is settled at the full price. In a two-way dead heat for first, half the stake is paid as a winner and half is lost. In a three-way dead heat, a third of the stake wins. £12 at 9/1 in a three-way dead heat for first is settled as £4 at 9/1, which returns £40.

A dead heat for a paying place in an each way bet works the same way on the place part. The place stake is split between the horses sharing the places that remained.

When Rule 4 and a dead heat both apply

It is unusual, but it happens. Take £10 at 8/1 with a 10p Rule 4 deduction, on a horse that then dead heats for first with one other.

First the deduction: 8/1 becomes 7.2 to 1. Then the dead heat: half the stake, £5, is paid at 7.2 to 1, which returns £41. The other £5 is lost. Doing the two steps in that order, price first and stake second, gives the right answer every time.

Which horse the deduction belongs to

The most common mix-up with Rule 4 is about which horse the deduction is linked to. The withdrawn horse sets the size of the deduction, but the deduction is applied to your bet on a different horse, the one that ran. Your own horse’s price has nothing to do with the size of the cut. A 40p deduction takes 40% off the winnings on a 2/1 winner and on a 20/1 winner alike.

So when a settlement says “R4 25p”, the question is not what price your horse was. It is what price the horse that came out was, at the moment it came out.

Checking a settlement

If a return looks wrong and Rule 4 is mentioned, three questions settle it. What price was the withdrawn horse when it came out? Was your bet struck before or after the withdrawal? And was it at a fixed price or at SP? With those answers and the table above, any deduction can be checked by hand, and the calculator below does it for you on the horse you backed.

A last aside. The price of the withdrawn horse is its price at the time of withdrawal, not its opening price. A horse that opened at 5/1 and was a well-backed 5/2 when it was withdrawn triggers the 25p deduction, not the 15p one. The market moved, and the deduction follows the market at the moment the horse left the race, which is the fairest measure of what its absence changed.