The 36-Month Stamp Duty Refund Window — Everything You Need to Know

Why the 36-Month Rule Exists

When you buy a new main home before selling your previous one, you temporarily own two residential properties. HMRC treats this as an additional dwelling purchase and charges the 5% surcharge at completion. The 36-month rule is the mechanism that allows you to reclaim that surcharge: if you sell the previous home within three years, the taxman acknowledges that the surcharge was not really warranted and gives it back.

The rule is generous in its window — three years is a long time — but it is absolute. Miss the deadline by a single day, and no statutory refund is available.

How the Clock Starts

The 36-month period begins on the **date you completed on your new property purchase**, not on:

• The date you put your old home on the market
• The date you accepted an offer on the old home
• The date you exchanged contracts on the sale of the old home
• The date you moved out of the old home

Only the completion date of the new purchase matters as the start point.

**Example:** You completed on your new home on 15 March 2024. Your 36-month deadline is 15 March 2027. If your old home completes its sale on 14 March 2027, you can claim. If it completes on 16 March 2027, you cannot.

When the Clock Ends — What "Disposal" Means

The relevant event that stops the clock is the disposal of your previous main home. In most cases, this means the completion of the sale. However, a disposal can also include:

• A gift of the property (transferring it to someone else for no consideration)
• A transfer pursuant to divorce or dissolution of civil partnership
• A sale at undervalue to a family member

In all these cases, the disposal must be complete — not merely contracted — before the 36-month deadline. Exchange of contracts on the sale of your old home does not count; completion does.

Monitoring Your Own Deadline

Your solicitor should advise you of the 36-month deadline at the time of your new purchase. Unfortunately, many do not follow up on this beyond the initial transaction. It is worth:

• Making a note of your completion date and adding a calendar reminder 30 months after completion (six months before the deadline, giving you time to act)
• Keeping your SDLT5 certificate in a safe place — you will need the transaction reference to make the claim
• Ensuring your estate agent is aware that the sale needs to complete within the window, not merely exchange

Was There Ever a COVID Extension?

During the COVID-19 pandemic, HMRC extended the 36-month window for certain transactions where the disposal of the previous home was delayed due to pandemic restrictions. These extensions applied specifically to cases where the 36-month period would have expired between 1 January 2020 and 31 December 2022. Those extensions have now ended, and no equivalent extension exists for any transactions at this time.

If your 36-month window falls in 2025, 2026 or 2027, the standard rules apply without any extension.

What Happens If the Sale Falls Through?

A sale that falls through before completion does not constitute a disposal. If your buyer pulls out, your 36-month clock keeps running from the original purchase date. You must relist, find a new buyer, and complete the sale within whatever time remains in the original window. See our guide on what to do if your sale falls through for practical steps.

Joint Purchases — Whose Previous Home?

In a joint purchase, the surcharge applies if any buyer is replacing their previous main home and has not yet sold it. The 36-month rule and refund applies once the relevant buyer's previous home is sold. Where both buyers previously owned properties and are selling at different times, the refund position should be reviewed by a solicitor.

Use our Stamp Duty Refund Calculator at Property Passport UK to calculate exactly how much surcharge you are entitled to reclaim, and note your deadline — then act well before it expires.