Stamp Duty When Downsizing: Retirement Property & the 36-Month Rule

Stamp Duty When Downsizing: The Basics

Downsizing, that is selling a large family home and buying a smaller property in retirement, is one of the most common property moves in the UK. For stamp duty purposes, the critical question is: at the point of completing your new purchase, how many residential properties do you own?

If you sell the old home and buy the new one simultaneously (or sell first), you own only one property at completion. The surcharge does not apply. If you buy the new home before the old one is sold, you momentarily own two properties. The surcharge applies.

Use our second home calculator to calculate exactly how much the surcharge would add to your purchase, and our replacement main residence rules guide for detailed exemption criteria.

April 2025 rate changes and what they mean for downsizers

The stamp duty nil-rate band dropped from £250,000 to £125,000 on 1 April 2025. For downsizers purchasing a smaller retirement property, say a £200,000 flat or bungalow, this change makes a meaningful difference to the base SDLT before any surcharge is considered. Under the new rates, £75,000 of that purchase falls within the 2% band rather than being nil-rated. This adds £1,500 to the standard SDLT compared to the old rates.

The surcharge, by contrast, is calculated at a flat 5% on the whole purchase price, so the April 2025 change has no direct effect on the surcharge amount. But the combined SDLT bill for buying-before-selling is now higher than it was pre-April 2025, making careful timing even more important.

The Replacement Main Residence Exemption

The replacement main residence exemption is the primary relief for downsizers. It provides that if you are genuinely replacing your only or main residence, by selling your old home and buying a new one, the additional dwelling surcharge does not apply.

The key conditions are:

• The old property must have been your main residence at some point. It cannot be a rental or investment property you are selling
• You must be selling the old property and buying the new one, so that you end up with only one home after the transactions
• The sale and purchase should ideally complete on the same day, but the 36-month rule provides a safety net (see below)

If you own other properties besides the main residence (a buy-to-let, a holiday home), the replacement main residence exemption still applies to the main residence element, but the other properties remain counted for surcharge purposes.

What counts as your "main residence"?

HMRC uses a facts and circumstances test to determine which property is your main residence. The key indicators are: where you spend the majority of your time, where you are registered to vote, where you receive correspondence, which address you use for tax and government purposes, and where your family lives. No single factor is conclusive, but the overall pattern matters.

Retirees who own a family home and a holiday cottage or second property may need to think carefully about which qualifies as their "main residence" for these purposes. If the holiday property was used more extensively in later years and could arguably be their main residence, the distinction has implications for both the SDLT replacement main residence exemption and capital gains tax private residence relief. Getting clarity on this before planning a property move is advisable.

The 36-Month Surcharge Refund Rule

The 36-month rule allows downsizers (and other home movers) who paid the surcharge on a new purchase to reclaim it, provided they sell their previous main residence within 36 months of the new purchase completing.

The refund process:

1. 1Purchase new property → pay the 5% surcharge at completion
2. 2Sell the old main residence within 36 months of the new purchase
3. 3File an SDLT amendment with HMRC within 12 months of the sale completing
4. 4HMRC refunds the surcharge amount

For full details on the refund claim process, see our stamp duty refund complete guide.

Buying Before You Sell: Chain Complications

In retirement downsizing, the "buy before sell" scenario is common. Many retirees prefer to secure their new property before selling the family home, avoiding the stress of being in a chain or needing temporary accommodation. The stamp duty consequence is:

• Pay the 5% surcharge on the new property at completion
• Reclaim the surcharge if you sell the old home within 36 months
• The refund is not instant: it requires an SDLT amendment after the sale

The financial cost is a temporary cash flow issue: you must have sufficient funds to pay the surcharge at completion, even if you expect to recover it later. For large purchases, this could be a significant sum to have available for months or even years.

A practical consideration: if the retiree is funding the new purchase partly from the proceeds of selling the old home, the "buy before sell" structure may require bridging finance to cover the period between the new purchase completing and the old home sale completing. Bridging finance carries its own costs: interest rates are typically 0.5–1% per month. These costs need to be weighed against the convenience of securing the new property before listing the old one.

To initiate the refund, you or your solicitor must write to HMRC (or file an online SDLT amendment) within 12 months of the old property sale completing. The amendment references the original SDLT return and claims repayment of the surcharge element. HMRC aims to process refunds within 15 working days. Retain completion statements from both transactions as supporting evidence.

Keeping the Old Home as a Rental: The Surcharge Trap

Some retirees consider keeping the family home as a rental property rather than selling, while moving to a smaller retirement property. The stamp duty implications are significant:

This means keeping the old home as a rental effectively doubles the cost: you pay standard SDLT on the new purchase, plus 5% surcharge on the full purchase price, with no prospect of recovery.

If you intend to rent out the old property long-term and simultaneously buy a smaller retirement home, factor the surcharge into your planning from the outset, as it is a permanent additional cost of the strategy.

There is, however, one scenario where retaining the old home is tax-efficient despite the surcharge: if the old home is expected to generate strong rental income or significant capital appreciation. In that case, the surcharge becomes an investment cost to be weighed against projected returns. The surcharge at 5% on a £400,000 property is £20,000, a cost that a high-yielding rental or appreciating asset may justify over a 10-year horizon. The key is to make the decision deliberately with full knowledge of the surcharge cost, rather than being caught by surprise.

Timing Your Move for Stamp Duty Efficiency

The optimal timing strategy to minimise stamp duty when downsizing:

• Best: Simultaneous exchange and completionExchange contracts on the sale of the old home and the purchase of the new home on the same day (or sell first). At completion, you own only the new property. No surcharge.
• Acceptable: Buy before sell, sell within 36 monthsPay the surcharge upfront, reclaim after selling the old home within the 36-month window. Requires cash flow to cover the surcharge and discipline to claim the refund in time.
• Risky: Buy before sell, uncertain sale timelineIf the old home proves difficult to sell, or the market weakens, you may miss the 36-month window. After 36 months, the surcharge is permanent and non-refundable.
• Expensive: Buy new, keep old as rentalPermanent surcharge, no refund available. Factor this into the economics of the rental strategy from the start.

Scotland (LBTT) and Wales (LTT) Rules

Scotland: LBTT & ADS

In Scotland, the Land and Buildings Transaction Tax (LBTT) applies instead of SDLT. The Additional Dwelling Supplement (ADS) is Scotland's equivalent of the surcharge, now 8% from December 2024 (up from 6%). The same principle applies: if you are replacing your main residence, ADS does not apply. If you buy before selling, you pay ADS and can reclaim it if you sell within 36 months.

The higher ADS rate in Scotland (8% vs 5% in England) makes the cash flow impact of buying before selling more significant. For a £200,000 Scottish property, the ADS would be £16,000 compared to £10,000 in England.

Wales: LTT

Wales uses Land Transaction Tax (LTT). The higher residential rates (5% from December 2024) apply when you own an additional property. The replacement main residence exemption and 36-month refund rules function identically to England: sell within 36 months and claim within 12 months of the sale.

An important cross-border consideration for retirees: if you sell your home in one nation and buy in another, for example selling an English property and moving to Scotland, the SDLT/LBTT distinction affects which tax authority handles your refund claim. The refund claim must be filed with the tax authority that received the original surcharge payment. If you paid SDLT in England, you claim from HMRC. If you paid ADS in Scotland, you claim from Revenue Scotland. Keep jurisdiction in mind when planning cross-border moves.