When Do You Pay Stamp Duty? Deadlines, Penalties, and the SDLT Return

The 14-Day SDLT Deadline

Since March 2019, Stamp Duty Land Tax must be paid and the SDLT return filed with HMRC within **14 days** of the effective date of the transaction. For most residential purchases, the effective date is the date of completion — the day you get the keys.

This replaced the previous 30-day window, which applied before 2019. Many conveyancing clients and even some advisers have residual memories of the older, longer deadline. It is 14 days now, and HMRC applies it strictly.

What Is an SDLT Return?

An SDLT return is the legal notification to HMRC that a land transaction has occurred. The primary form is SDLT1, with supplementary forms SDLT2–SDLT4 used for transactions involving multiple parties, multiple properties, or leases.

The return must include:

• The address and description of the property
• The purchase price and the amount of SDLT due
• The buyers' details (name, address, National Insurance number)
• Whether any reliefs are claimed
• The effective date of the transaction

HMRC issues a SDLT5 certificate upon receipt of the return and payment, which your solicitor uses to register the title transfer at HM Land Registry. Without the SDLT5, registration cannot proceed.

Who Is Responsible for Filing?

In practice, your solicitor or licensed conveyancer files the SDLT return on your behalf as part of the conveyancing process. The cost is typically included in their conveyancing fee.

However, the legal obligation to ensure the return is filed and tax paid rests with the buyer. If your solicitor fails to file on time — which is rare but not unknown — HMRC will look to you for the penalties and interest.

If you are handling your own conveyancing (permitted for straightforward freehold purchases but strongly discouraged), you must file the SDLT return yourself using HMRC's online portal.

Penalties for Late Payment

HMRC's penalty structure for late SDLT returns is automatic and escalating:

• **Day 1 (filing date missed):** £100 automatic penalty
• **After 3 months:** £200 additional penalty
• **After 12 months:** Further penalty of the greater of £300 or 5% of the SDLT due (if HMRC believes the failure was deliberate, the penalty can be up to 100% of the tax due)
• **Interest:** HMRC charges interest on late paid SDLT from the day after the due date, compounding daily

For small SDLT liabilities, the £100 day-one penalty may exceed the tax itself. For larger transactions, the consequences are more serious.

Checking Your SDLT Return Was Filed

Your solicitor should provide you with a copy of the SDLT5 certificate after completion. This is your proof that the return was filed and the SDLT paid. Keep this document safely — you may need it years later when selling the property.

If you did not receive an SDLT5 certificate, contact your solicitor and ask for confirmation. You can also check with HMRC's SDLT helpline (0300 322 7835) that a return has been received for your property.

Can You File the Return Yourself?

Yes. If you need to file the return yourself — either because you conducted your own conveyancing or because you need to amend a return — the HMRC SDLT online portal is at www.gov.uk/stamp-duty-land-tax/returns. You will need a Government Gateway account.

You can also file by post using a paper SDLT1 form, but this takes longer and is not recommended given the 14-day deadline.

Amending an SDLT Return

If an error is discovered in the SDLT return after filing — for example, if the wrong relief was claimed, or the property details were incorrect — the return can be amended within **12 months of the original filing date**. Amendments are made through the same HMRC portal. If the amendment results in additional tax being due, interest applies from the original due date. If it results in a repayment, HMRC processes the refund.

SDLT in the Context of Your Purchase

Your solicitor will typically request the SDLT funds from you before or on completion day, alongside the balance of the purchase price. Ensure you have budgeted for SDLT as part of your completion funds — it cannot be added to your mortgage.

Use our Stamp Duty Calculator at Property Passport UK to calculate your exact SDLT liability well before completion, so you can ensure the right amount is ready in advance and there are no last-minute surprises.