Rule 4 Deductions Explained: Horse Racing Betting Rules Guide
Learn how Rule 4 deductions work in horse racing, how the Tattersalls scale determines your payout, and how to protect your winnings when a non-runner is declared.
Category: Guides · By Growl Games Editorial Team · Thu Sep 03 2026 · Updated Thu Sep 03 2026
Rule 4 deductions are one of the most frequently misunderstood elements of horse racing betting — and one of the most financially significant. If a horse is withdrawn from a race after the betting market has opened, the bookmaker cannot simply cancel all bets; the odds on the remaining runners have already changed, and the market needs rebalancing. Rule 4 deductions are the mechanism that achieves that rebalancing, protecting the integrity of payouts while ensuring bookmakers do not pay out at odds that were never genuinely available.
This guide explains how rule 4 deductions work in practice: where the scale comes from, how to calculate exactly what will be deducted from your winnings, and how to structure your horse racing bets so a late withdrawal never catches you off guard. Whether you're new to racing or a seasoned each-way punter, understanding Rule 4 is non-negotiable.
What Is a Rule 4 Deduction?
A Rule 4 deduction is a percentage reduction applied to winnings on a horse racing bet when a horse is withdrawn from a race before the off. The name comes from Rule 4(c) of the Tattersalls Rules of Racing, the industry-standard framework that governs how UK and Irish bookmakers handle non-runners.
When you place a bet on a horse and a shorter-priced rival is subsequently scratched, the effective probability of your selection winning has increased — the field is now weaker. Bookmakers cannot pay you at the original odds because those odds were set against a field that included the withdrawn horse. The Rule 4 deduction reduces your payout to reflect the true odds of the race that actually took place.
The Tattersalls Rules: Where Rule 4 Comes From
Tattersalls — formally Tattersalls Committee — is the historic authority that codified standard betting rules for British racing. Their Rules of Racing have been adopted by the vast majority of UK bookmakers and are recognised by the UK Gambling Commission as the baseline framework for settling racing bets. Rule 4(c) specifically addresses non-runners and sets out a sliding scale of deductions based on the starting price (SP) of the withdrawn horse at the time of withdrawal.
The logic is actuarially sound: the shorter the withdrawn horse's price, the greater the probability it represented, and therefore the larger the adjustment needed to the remaining field's implied probabilities. A 5/4 favourite withdrawn at the last moment distorts the market far more than a 50/1 outsider.
The Rule 4 Deduction Scale Explained
The deduction percentage is determined by the odds of the withdrawn horse at the time of withdrawal — not their morning-line price or ante-post odds. The official Tattersalls scale is as follows:
| Withdrawn Horse's Odds | Deduction from Winnings | Example: £100 Winnings |
|---|---|---|
| 1/9 or shorter (odds-on favourite) | 75p in the £ | You receive £25 |
| 2/11 to 1/4 | 70p in the £ | You receive £30 |
| 30/100 to 2/7 | 65p in the £ | You receive £35 |
| 1/3 to 2/5 | 60p in the £ | You receive £40 |
| 4/9 to 1/2 | 55p in the £ | You receive £45 |
| 8/15 to 4/6 | 50p in the £ | You receive £50 |
| 8/13 to 4/5 | 45p in the £ | You receive £55 |
| 5/6 to 20/21 | 40p in the £ | You receive £60 |
| Evens to 6/5 | 35p in the £ | You receive £65 |
| 5/4 to 6/4 | 30p in the £ | You receive £70 |
| 13/8 to 7/4 | 25p in the £ | You receive £75 |
| 15/8 to 9/4 | 20p in the £ | You receive £80 |
| 5/2 to 3/1 | 15p in the £ | You receive £85 |
| 10/3 to 4/1 | 10p in the £ | You receive £90 |
| 9/2 to 11/2 | 5p in the £ | You receive £95 |
| 6/1 to 9/1 | Nil (no deduction) | You receive £100 |
| 10/1 or longer | Nil (no deduction) | You receive £100 |
When two or more horses are withdrawn from the same race, deductions are combined — but the total maximum deduction is capped at 75p in the £. No matter how many horses scratch, you will always receive at least 25% of your notional winnings.
Step-by-Step Walkthrough: Calculating Your Payout
Abstract percentages only become meaningful with real numbers. Here are two scenarios that cover the most common situations punters encounter.
Your bet: £20 each-way on Desert King at 8/1 (Win + Place)
Non-runner: Windstorm, who was trading at 1/2 (odds-on) at time of withdrawal
Deduction applied: 55p in the £ (per the scale above)
Win part of your bet: £20 × 8/1 = £160 winnings. After 55p deduction: £160 × 0.45 = £72.00 + your £20 stake returned = £92.00
Place part of your bet: Assuming 1/5 odds (1.6/1 effective), £20 × 1.6/1 = £32 winnings. After deduction: £32 × 0.45 = £14.40 + £20 stake = £34.40
Without the Rule 4 deduction, the win part alone would have paid £180. The practical impact of a heavy-odds non-runner is substantial.
Your bet: £10 win on Foxglove at 5/1
Non-runner 1: Traded at 2/1 at withdrawal → 15p deduction
Non-runner 2: Traded at 4/1 at withdrawal → 10p deduction
Combined deduction: 15 + 10 = 25p in the £
Notional winnings: £10 × 5/1 = £50. After 25p deduction: £50 × 0.75 = £37.50 + £10 stake = £47.50
Had both non-runners been very short-priced, the deductions would cap at 75p, protecting a minimum return of 25% of winnings.
When Rule 4 Is and Isn't Applied
Bookmakers do not apply Rule 4 automatically in every non-runner scenario. Several conditions govern whether a deduction will be made:
Rule 4 DOES Apply When:
- Bet was placed before the non-runner was declared
- The race is a standard flat, jump, or National Hunt fixture
- The horse was listed in the final declared field
- The withdrawal occurs after the market has opened
- The non-runner's price at withdrawal falls within the deduction scale (under 10/1)
- Multiple non-runners in the same race (cumulative, capped at 75p)
Rule 4 Does NOT Apply When:
- Bet was placed after the withdrawal was announced
- The non-runner's odds were 10/1 or longer at time of withdrawal
- The bookmaker offers "Non-Runner No Bet" (NRNB) on that market
- The withdrawal is a declared non-runner before any market opened
- Ante-post bets (special terms apply — typically no refund)
- Bets on virtual or simulated racing
Important: Each bookmaker may apply Rule 4 slightly differently in edge cases — for instance, some apply it to the total return (stake + profit) rather than profit only in certain bet types. Always check your bookmaker's individual terms before placing complex multiples on horse racing.
Rule 4 Deductions vs. Non-Runner No Bet
Over the past decade, many bookmakers have introduced Non-Runner No Bet (NRNB) as an alternative settlement rule, typically offered on major races like the Cheltenham Festival, Royal Ascot, and the Grand National. Understanding the difference is critical when choosing where to place your bet.
| Feature | Standard Rule 4 | Non-Runner No Bet (NRNB) |
|---|---|---|
| Non-runner outcome | Bet stands, winnings reduced by deduction % | Full stake refunded, bet voided |
| Stake returned? | Yes (stake is always returned) | Yes (full refund) |
| Winnings affected? | Yes — reduced per scale | No — you simply rebid |
| Available races | All races (default rule) | Selective — major festivals/races only |
| Best for punters when | Non-runner was very long-priced (no deduction) | Ante-post / big-field races with withdrawal risk |
| Operator risk | Lower — operator hedges via deduction | Higher — operator absorbs non-runner risk |
NRNB is unambiguously better for the punter when the withdrawn horse was a short-priced favourite — you get your stake back rather than a reduced payout. Seek it out on major race days where fields are volatile. On smaller meetings, standard Rule 4 terms will apply.
Betting Smart Around Rule 4
Rule 4 deductions cannot be avoided when they apply — but they can absolutely be anticipated and managed. Experienced horse racing bettors factor potential withdrawals into their decision-making from the outset.
Identify High-Risk Races Before Betting
Large-field handicaps — particularly novice hurdles, big staying handicaps, and races run on soft/heavy ground — carry elevated withdrawal risk. Races with declared fields of 18+ runners are statistically more likely to see non-runners on the day, as horses are subject to late veterinary checks.
Time Your Bet Strategically
Early morning prices often represent value — but they also carry the greatest Rule 4 risk. If you place a bet 48 hours before the race and the odds-on favourite is subsequently withdrawn, your deduction will be heavy. Betting closer to the off time, once non-runners have been declared, significantly reduces (but does not eliminate) deduction risk. The trade-off is that prices shorten as the field clears.
Use NRNB Markets Where Available
On any race where a bookmaker offers both standard and NRNB markets, the NRNB option is almost always preferable for high-value selections in competitive fields — even if the odds are marginally shorter. The insurance against heavy deductions more than compensates in expectation.
Understand Each-Way Implications
Rule 4 deductions apply independently to both the win part and the place part of an each-way bet. When a short-priced favourite is withdrawn, the field shrinks — bookmakers may also reduce the number of places paid. Check the updated place terms after any major withdrawal before assuming your each-way is still viable.
Keep a Record of Deductions
Serious bettors track not just their wins and losses but the Rule 4 deductions taken across their racing bets over a season. This data can reveal patterns — for example, whether backing in large-field handicaps is systematically eroding profitability due to frequent deductions — and inform future staking decisions.
Why Growl Games for Horse Racing Betting
Understanding Rule 4 puts you ahead of most recreational punters — and having the right platform matters just as much. At Growl Games, our sportsbook covers UK and international horse racing with competitive pre-race and in-play markets, clear settlement rules applied transparently at payout, and NRNB available on selected feature races. Fast withdrawals mean you never wait long to reinvest your winnings, and our welcome bonus gives new members added value from the first bet. If horse racing is part of your betting portfolio, Growl Games is built to support it properly.
Frequently Asked Questions
What is a Rule 4 deduction in horse racing?
A Rule 4 deduction is a percentage reduction applied to your winnings when a horse is withdrawn from a race after your bet was placed. It is named after Rule 4(c) of the Tattersalls Rules of Racing and is designed to compensate for the fact that the odds on remaining runners were inflated by the presence of the now-withdrawn horse. The percentage deducted depends on the odds of the non-runner at the time of withdrawal — the shorter the price, the higher the deduction, ranging from 5p in the £ for horses at 9/2–11/2 up to 75p in the £ for 1/9 or shorter. Your original stake is always returned in full; only the profit portion is subject to deduction.
Does Rule 4 apply if I bet after a horse is withdrawn?
No. Rule 4 only applies to bets placed before the withdrawal was announced. If you place your bet after the non-runner has been declared, the remaining runners' odds will already reflect the revised field, and no deduction will be applied. This is why bookmakers issue withdrawal notices promptly — any bets accepted after that point are settled at the revised odds with no Rule 4 adjustment needed.
What happens when multiple horses are withdrawn from the same race?
When more than one horse is withdrawn, the applicable deduction percentages are added together. For example, if two horses are withdrawn — one at odds of 2/1 (15p deduction) and another at 5/2 (15p deduction) — the combined deduction is 30p in the £. However, regardless of how many non-runners there are or how short their prices, the total combined Rule 4 deduction is capped at 75p in the £. This means you will always receive at least 25% of your notional winnings, even in the extreme scenario of multiple short-priced horses being scratched.
Do Rule 4 deductions apply to each-way bets?
Yes — Rule 4 deductions apply to both the win part and the place part of an each-way bet independently. In addition to the deduction, you should be aware that a major withdrawal can also prompt bookmakers to revise the number of places paid. If the field drops below a certain threshold, a race that originally paid four places may revert to three or even two. Always confirm the updated place terms with your bookmaker after a significant non-runner has been declared, especially in large-field handicaps where each-way terms are most valuable.
What is the difference between Rule 4 and Non-Runner No Bet?
Under standard Rule 4 terms, your bet stands when a horse is withdrawn but your winnings are reduced by the applicable percentage. Under Non-Runner No Bet (NRNB), your bet is simply voided and your full stake is refunded if a non-runner is declared — giving you the option to rebid at revised odds. NRNB is significantly more favourable to the punter when the withdrawn horse was a market leader, because it eliminates the risk of a heavy deduction. NRNB is typically only offered on major racing festivals and selected feature races, not as the default for everyday fixtures.
Are Rule 4 deductions applied to ante-post bets?
Generally, no — ante-post bets operate under different terms entirely. With ante-post betting, if your selection does not run for any reason, you typically lose your stake with no refund (unless the bookmaker has stated NRNB applies ante-post, which some do for certain marquee events). Rule 4 deductions are a race-day mechanism for declared-runners markets. The key risk with ante-post betting is precisely that non-runners result in lost stakes rather than reduced winnings, which is why the longer-price value must justify the additional risk.
"The shorter the withdrawn horse's price, the greater its implied probability — and the larger the adjustment your payout needs. Rule 4 isn't a penalty; it's the market correcting itself."— Daniel Cole