The Mathematics
Convert the accepted odds to decimal, multiply by the stake, and separate the profit from the stake return. A deduction of 25p per pound removes 25% of that profit, leaving 75%. Add the unchanged stake back to obtain the adjusted total return. The deducted amount is not 25% of the total payout. The applicable deduction depends on the withdrawn horse's price and market circumstances, not the price of the horse you backed.
Gross profit = stake × (decimal odds − 1)
Deduction fraction = announced pence ÷ 100
Adjusted profit = gross profit × (1 − deduction fraction)
Adjusted return = stake + adjusted profit
Adjusted decimal price = 1 + (original decimal − 1) × (1 − deduction fraction)
Worked Example
A £10 cash winner at 4/1 has £40 gross profit and £50 gross return. If a 25p Rule 4 applies, £40 × 0.25 = £10 is deducted. Adjusted profit is £30 and adjusted return is £40, including the unchanged £10 stake. A withdrawal at 5/2 falls in the standard 25p band. The official Sky Bet scale puts 2/1 in the 30p band instead.
How do I use the Rule 4 calculator?
Enter the stake on your winning cash bet and the accepted fractional odds, such as 4/1. Choose the deduction announced for your ticket in Rule 4 Deduction. The price descriptions beside the choices refer to the withdrawn horse, not your winner. If the bookmaker states 25p, choose 25p even if your backed horse was 4/1. The tool does not retrieve withdrawals or determine which market your bet belonged to.
Read Gross Return as the unadjusted cash payout, Rule 4 Deduction as money removed from gross profit, and Adjusted Return as the amount after that reduction. Adjusted Profit excludes the original stake. At zero deduction the two returns match. The displayed calculation assumes your horse wins outright; it has no loss, void or dead-heat state, and it is not a combined settlement engine.
Which prices determine a standard deduction?
The relevant price is the withdrawn selection's price at withdrawal under the operator's market rules. As familiar reference bands, 15/8 through 9/4 corresponds to 30p, 5/2 through 3/1 to 25p, and 10/3 through 4/1 to 20p. Shorter withdrawn prices normally produce larger reductions. Do not infer a horse's actual probability from a band: the scale is a settlement rule.
Operators can waive certain small deductions. The published bet365 withdrawal rules, for example, state that it abolishes the first 5p deduction for a withdrawal between 10/1 and 14/1. This illustrates why the settled slip's announced deduction should take precedence over a generic table. Multiple withdrawals and reformed markets can affect different tickets differently depending on when prices were accepted.
How do multiple withdrawals and price changes affect settlement?
A total reduction can reflect more than one non-runner, and standard rules cap combined deductions at 90p per pound. Do not blindly multiply separate deductions as though each is applied to the already-reduced profit. Use the operator's final deduction for the original or reformed market. A bet placed after one withdrawal can have a different applicable deduction from a bet placed earlier at the same quoted price.
If your own selection is a non-runner under ordinary terms, the question is usually a void and refund, not a Rule 4 reduction to a hypothetical win. Ante-post all-in terms may behave differently. Best odds guaranteed can also alter the final settlement price under qualifying conditions. This form neither identifies ante-post terms nor decides whether a starting-price concession overrides an earlier adjusted quote.
How does Rule 4 differ from a dead heat or commission?
Rule 4 preserves the winning cash stake and reduces profit odds. A simple dead heat divides the return attributable to the relevant winning portion, including its stake element. At £10 and 4/1, a 25p Rule 4 gives £40 return, whereas a two-horse win dead heat gives £25 before any Rule 4. Treating these as the same percentage adjustment would produce the wrong result.
For an affected double leg at decimal 5.00 with a 25p deduction, its adjusted decimal is 4.00. If the other leg is decimal 3.00, a £10 double returns £120, not the original £150. Cutting the final £140 ticket profit by 25% would give £115, which is different and incorrect for that single affected leg. This tool handles one winning cash leg only; each way, multiples, exchange reduction factors and fees need the appropriate separate rules.
Popular questions about this calculator
Is Rule 4 taken from profit or total return?
From the winnings or profit portion of the affected cash bet, not its returned stake. A £10 winner at 4/1 has £40 profit; a 25p deduction removes £10. The adjusted return is £40, not £37.50, which would incorrectly reduce the full £50 payout.
What Rule 4 applies when a 2/1 horse is withdrawn?
The official Sky Bet scale puts 2/1 within the 15/8 to 9/4 band, corresponding to 30p per pound of winnings. The 25p band is 5/2 to 3/1. Confirm the deduction actually announced for your accepted bet, because market timing and operator concessions can matter.
Which horse's odds do I use for the deduction?
The withdrawn horse's relevant price determines the deduction band. Your backed winner's accepted odds determine its gross profit. These are different inputs: do not choose a band from your own selection's price unless it happens to match the withdrawn horse.
Does a 25p deduction mean losing 25% of my stake?
No. It removes 25% of the affected winning profit. The original cash stake is returned unchanged on an outright winner. At £10 and 4/1, £10 is deducted from £40 profit, leaving £30 profit plus the £10 stake.
Can more than one Rule 4 apply?
Yes. Multiple withdrawals can contribute to the final deduction, with standard combined reductions capped at 90p per pound. Use the bookmaker's announced total and the correct original or reformed market. The calculator accepts one deduction value, not a chronological list of withdrawals.
What if I placed my bet after the withdrawal?
A bet placed in a reformed market can have different deduction exposure from an earlier bet. Later withdrawals may still matter. Check the accepted bet time, market and operator's notice rather than assuming all tickets on the race receive the same adjustment.
Does Rule 4 apply when my own horse is a non-runner?
Under ordinary non-runner terms your bet is normally void and the stake refunded. Rule 4 generally concerns affected bets on the remaining runners. Ante-post all-in terms can differ. This calculator illustrates an outright winning cash bet, not a withdrawal refund.
Can I apply Rule 4 to the final profit of an accumulator?
Not as a blanket shortcut when only one leg is affected. Adjust that leg's decimal profit odds, add one back, then multiply the adjusted leg with the other decimal prices. The calculator here handles one leg and does not assemble an adjusted multiple.
Is a betting-exchange reduction factor the same as Rule 4?
No. Exchange markets have their own reduction-factor and settlement rules, and commission is a separate issue. A fixed-odds Rule 4 calculator should not be used as an automatic exchange settlement model. Consult the rules attached to the relevant market.
Does the calculator combine Rule 4 and a dead heat?
No. It has one deduction control and assumes an outright cash winner. A dead heat changes the successful stake portion, so the combined settlement requires both rules to be applied correctly. Use the separate dead-heat explanation and confirm complex payouts with the operator.
Official rules and further reading
These operator references explain bet structures and settlement rules. They are not endorsements, and the terms attached to your accepted bet take precedence. Worked amounts on this page are illustrative arithmetic, not live odds or promised outcomes. Only gamble money you can afford to lose; a returns tool does not make a bet safe.