Rule 4 Calculator
Dead Heat Calculator
Two or more runners finished level? Enter how many dead-heated and how many places they share to see the payout.
How To Use This Calculator
Enter your stake, the odds you took, and the deduction the bookmaker announced. The calculator shows your adjusted return next to what you would have collected without the withdrawal, for win and each-way bets.
Add your stake and the odds you took, fractional (5/1) or decimal (6.0). Switch to each-way mode for two-part bets.
Choose the announced deduction, from 5p to 90p in the pound, or type a custom figure. The table below shows the standard scale.
Compare the adjusted return against the original. For dead heats, use the second tool on this page.
What Is Rule 4?
Rule 4 is a standard deduction applied to winning horse racing bets when a runner is withdrawn after you placed your bet. With one horse out of the race, every remaining runner has a better chance of winning, so the odds you locked in are suddenly too generous. The deduction, quoted in pence per pound of winnings, corrects for that.
The scale comes from the Tattersalls Committee Rules on Betting, which is why it is often called a Tattersalls Rule 4. The shorter the withdrawn horse's price, the bigger its chance was, and the more comes off your winnings. Your stake is never touched.
The Standard Tattersalls Rule 4 Table
The deduction is set by the withdrawn horse's price at the time it comes out, not by your horse's price. This is the scale published in the Tattersalls Committee Rules on Betting; many bookmakers apply it or a close variant, and exact terms vary by bookmaker.
| Price of withdrawn horse | Deduction |
|---|---|
| 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 |
| 1/1 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 |
| Over 14/1 | No deduction |
Deductions are quoted in pence per pound of winnings: 20p means 20% comes off your winnings.
If more than one horse is withdrawn, deductions are added together and capped at 90p in the pound under the standard rule.
Worked Example: 20p on a 5/1 Winner
You have $10 on a horse at 5/1 (decimal 6.0). Before the off a 4/1 rival is withdrawn and the bookmaker announces a 20p Rule 4 deduction. Your horse wins.
When Rule 4 Does Not Apply
Under the standard table, a horse withdrawn at over 14/1 triggers no deduction. Removing an outsider barely changes the rest of the market.
Bets struck once the new market has formed are already priced on the reduced field, so no deduction applies to them.
Traditional ante-post bets are generally settled all-in, run or not: no Rule 4 deduction, but no stake back if your horse never runs. Terms vary by bookmaker.
Some bookmakers advertise that they do not apply small deductions, commonly 5p, on selected races. Check the race terms rather than assuming.
How Dead Heats Are Settled
A dead heat is two or more runners finishing exactly level. The standard settlement divides your stake by the number of dead-heaters per place available, and the surviving share is paid at the full odds. In a two-way dead heat for the win, half your stake wins at full odds and the other half loses.
Example: $10 at 3/1, two-way dead heat for first place. Half the stake is settled as a winner, returning $20; the other $5 is lost. You collect $20 instead of the $40 a clean win would have paid.
In place markets the same logic applies to the places left for the dead-heaters. If three horses dead-heat for the final two places, each place bet is settled on two thirds of the stake. The dead heat tool above handles any combination of runners and places.
Frequently Asked Questions
What is a Rule 4 deduction?
Rule 4 is a deduction from winnings applied when a horse is withdrawn after you placed a fixed-odds bet. The deduction, quoted in pence per pound, reflects how much the withdrawal improved the chances of the remaining runners.
Why do bookmakers apply Rule 4?
Because a withdrawal reprices the whole race. If a fancied runner comes out, the true odds of every remaining horse shorten immediately. Without Rule 4, anyone holding a bet at the old odds would have a large, unearned edge on the reformed market.
How big can a Rule 4 deduction be?
The standard Tattersalls scale runs from 5p in the pound when the withdrawn horse was priced 10/1 to 14/1, up to 90p when it was 1/9 or shorter. A withdrawal at over 14/1 triggers no deduction. With several withdrawals, deductions add up and are capped at 90p.
Does Rule 4 apply to each-way bets?
Yes. The deduction comes off the winnings of both the win part and the place part. The calculator's each-way mode applies it to both and shows each part separately.
Does Rule 4 take money from my stake?
No. Rule 4 only reduces winnings. Your full stake is returned on a winning bet whatever the deduction; even at the maximum 90p you keep the stake plus 10% of the original winnings.
When does Rule 4 not apply?
When the withdrawn horse was priced over 14/1, when your bet was struck after the withdrawal at the reformed prices, and generally on ante-post bets, which are settled all-in. Some bookmakers also waive small deductions on selected races; terms vary.
How are dead heat bets paid out?
Your stake is divided by the number of runners in the dead heat, per place available, and the surviving share is paid at full odds. In a two-way dead heat for first, half your stake wins and half loses. The dead heat calculator on this page gives the exact figures.
Can Rule 4 and a dead heat hit the same bet?
Yes. If a rival is withdrawn and your horse then dead-heats, the dead-heat division is applied to your stake and the Rule 4 deduction is then taken from the winnings of the surviving share.
You cannot dodge Rule 4, but you can start ahead
A Rule 4 deduction is just the market correcting itself, and it works on whatever odds you took. What you control is taking overpriced odds in the first place. Bet Hero's value bet scanner compares bookmaker prices against the sharp market in real time, so the price you lock in starts ahead of the correction.