If you buy a property in England or Northern Ireland, you must file a Stamp Duty Land Tax return and pay any tax owed within 14 days of the transaction’s effective date, which is normally the completion date. Both the return and the payment share that same deadline. Miss it and HMRC issues an automatic £100 penalty, with interest running daily on any unpaid tax and further penalties stacking at three months and twelve months.
Two things to check before reading further. SDLT only applies to purchases in England and Northern Ireland.1GOV.UK. Stamp Duty Land Tax Overview Scotland has Land and Buildings Transaction Tax, Wales has Land Transaction Tax, and each has its own filing rules. And you do not need to file at all if the total consideration is £40,000 or less, or if the transaction is specifically exempt.2GOV.UK. Notifiable Transactions FA03/S77 and S77A Every other purchase of a freehold or leasehold interest above that threshold must be reported, even where no tax is owed.
When the 14-Day Clock Starts
The countdown runs from the “effective date” of your transaction. For most purchases that is the completion date, when keys change hands and the balance of funds is transferred.3GOV.UK. SDLT Changes to Periods for Delivering Returns and Paying Tax The date can also be triggered earlier if the contract is “substantially performed” before completion.
Substantial performance happens in one of two ways. Either you take possession of the property, or substantially all of it, before formal completion. Or 90 percent or more of the purchase price is paid before completion.4legislation.gov.uk. Finance Act 2003 Section 44 – Contract and Conveyance Either event starts the 14-day clock immediately, even though contracts have not yet formally completed. Exchanging contracts on its own does not trigger the deadline unless one of these conditions is met.
This catches people out. If your seller lets you move in early, or your solicitor releases nearly all of the purchase funds ahead of the formal completion date, the clock may already be running. Your conveyancer should flag it, but the trigger is worth understanding yourself.
The deadline used to be 30 days. It changed to 14 days in March 2019, so older guidance you find online will often quote the wrong window.5HM Revenue & Customs. Changes to the Stamp Duty Land Tax Filing and Payment Time Limits
How to File and Pay in the Window
Most returns are submitted through HMRC’s online portal, which gives immediate confirmation and generates an SDLT5 certificate once the return is accepted. Paper returns can be posted to HMRC’s dedicated address, but a paper return sitting in the post for three or four days eats badly into a 14-day window.6GOV.UK. Stamp Duty Land Tax Online and Paper Returns
The SDLT1 return asks for the effective date, the property address with a local authority number, the purchaser’s full name and address, and a National Insurance number for individual buyers. You also declare whether you are claiming any relief.7HM Revenue & Customs. How to Complete Your Stamp Duty Land Tax SDLT1 Return Returns get rejected for missing any one of these, so have everything ready before you start.
In practice, your solicitor or conveyancer handles the filing for most buyers. They will ask you for the identification details during the transaction and submit the return once completion happens. If you are managing the purchase yourself, the responsibility falls to you.
The SDLT5 Certificate
Once HMRC accepts the return and any tax is paid, it issues an SDLT5 certificate. You need this to register your ownership with HM Land Registry. Without it, the Land Registry will not update the title to reflect your purchase.6GOV.UK. Stamp Duty Land Tax Online and Paper Returns Your solicitor normally sends the SDLT5 on to the Land Registry as part of the registration application.
What It Costs to Miss the Deadline
The penalty regime escalates at fixed intervals, and HMRC does not send reminders before the penalties trigger. They are automatic.
- One day to three months late: a fixed £100 penalty as soon as HMRC does not receive the return within 14 days of the effective date.8GOV.UK. Penalties for Late Land Transaction Return SD7 Guide
- After three months: a further fixed £200 penalty on top of the initial £100.
- After twelve months: a tax-based penalty of up to the full amount of SDLT due on the transaction. On an expensive property that can effectively double the bill.
On top of the fixed penalties, HMRC charges interest on any unpaid SDLT from the day after the 14-day deadline until the tax is paid in full.6GOV.UK. Stamp Duty Land Tax Online and Paper Returns As of January 2026 the late payment interest rate is 7.75 percent per year.9GOV.UK. Rates and Allowances – HMRC Interest Rates for Late and Early Payments On a £15,000 SDLT bill, that works out to roughly £3.18 a day. Interest runs alongside the fixed penalties, so the total cost of delay grows faster than most people expect.
When HMRC Accepts a Reasonable Excuse
HMRC can cancel penalties where you had a genuine reasonable excuse for missing the deadline. The bar is high. “I forgot” or “I didn’t know about the deadline” will not work. Each case is judged on its own facts, but HMRC’s internal guidance recognises several categories:10GOV.UK. CH160300 – Reasonable Excuse – Examples of Reasonable Excuse
- The death of a partner or close relative that affected your ability to meet the deadline.
- A serious physical or mental illness, or a hospital stay, that prevented you from dealing with your tax affairs.
- Postal disruption where you posted the return in good time but it was lost or delayed due to industrial action, fire, or flood at the postal service.
- A failure of HMRC’s own online service, where the filing system would not accept your return or you could not access it due to a technical issue at HMRC’s end.
- Delayed activation codes, where you registered for online filing before the deadline but did not receive your activation PIN in time and filed as soon as it arrived.
- Loss of records to fire, flood, theft, or computer failure, where you could not reconstruct the information in time.
In every case HMRC expects evidence. A doctor’s note, a certificate of posting, or a screenshot of an error message all strengthen the claim. You also have to show that you filed as soon as the obstacle was removed. Sitting on the return for weeks after recovering from illness will undermine an otherwise legitimate excuse.
Fixing a Return After You File
If you spot an error after filing, or your circumstances change in a way that affects the tax calculation, you can amend the SDLT return within 12 months and 14 days of the original filing date. Common reasons include discovering you qualified for a relief you did not claim, or realising VAT should have been included in the purchase price (relevant mostly to commercial and mixed-use transactions, where the SDLT calculation is based on the VAT-inclusive price).11HM Revenue & Customs. Scope – How Much Is Chargeable – Interaction With VAT FA03/SCH4/PARA2
Amendments go through the same online portal or by letter to HMRC. Filing an amendment does not reset the original 14-day payment deadline. If more tax is owed as a result of the correction, interest may still run from the original due date.
The same 12-month window matters if you paid the additional dwellings surcharge on a replacement main home and then sold your previous property. You can claim the surcharge back, but you must apply within 12 months of either the sale date or the filing date of the SDLT return on the new property, whichever is later, and the sale itself has to happen within three years of the new purchase.6GOV.UK. Stamp Duty Land Tax Online and Paper Returns