Stamp Duty When Selling and Buying at the Same Time

Stamp Duty Land Tax is one of the largest upfront costs when buying a home in England and Northern Ireland. If you are selling one property and purchasing another at the same time, the rules can feel confusing — particularly when it comes to the higher rate surcharge for owning more than one property.

This guide explains exactly how SDLT works when you are in the middle of a simultaneous sale and purchase, including the current rates for 2026, when the surcharge applies, how to avoid it, and how to claim a refund if you end up paying it. If you are also budgeting for the full cost of your move, our guide to how much it costs to sell a house in 2026 covers every expense on the selling side.

How stamp duty works when you sell and buy

The first point to understand is that stamp duty is paid by the buyer, not the seller. When you sell your existing home, you do not owe any SDLT on that transaction. The buyer of your property pays their own stamp duty bill. Your stamp duty liability arises only on the property you are purchasing.

The complication comes when your purchase completes before your sale. If you own two residential properties at the end of the day on which you complete your purchase, HMRC treats you as buying an additional dwelling and applies the higher rate surcharge — an extra 5 percentage points on top of the standard SDLT rates. This surcharge applies to the entire purchase price, not just a portion of it.

However, if you are replacing your main residence and both transactions complete on the same day, the surcharge does not apply. This is why solicitors in property chains work hard to align completion dates — it is not just about convenience, it directly affects your tax bill. For more on how this works in practice, see our guide on what happens between exchange and completion.

Current SDLT rates in England and Northern Ireland (2026)

From 1 April 2025, the SDLT thresholds reverted to their pre-September 2022 levels. The current standard residential rates, as published by HMRC, are:

First-time buyers benefit from a nil-rate band of £300,000 on properties up to £500,000. This relief does not apply to existing homeowners selling and buying simultaneously, so the standard rates above are what you will pay.

The higher rate surcharge explained

The higher rate surcharge was introduced in April 2016 and increased from 3% to 5% in October 2024. It is designed to apply when a buyer purchases a residential property while already owning one or more other residential properties. The key rules are:

• The surcharge applies if, at the end of the day of your purchase, you own two or more residential properties and have not sold your previous main residence.
• It is charged on the entire purchase price, not just the amount above each threshold.
• Properties owned anywhere in the world count, not just UK properties.
• A property worth less than £40,000 is excluded from the count.
• The surcharge does not apply if you are replacing your main residence and the old property has been sold by the end of the day of the new purchase.

When the surcharge does not apply

If you are selling your only or main residence and buying a replacement, you will not pay the surcharge provided your sale completes on or before the day your purchase completes. This is the "replacement of main residence" exception and it is the most important rule for anyone in a simultaneous sale and purchase.

The exception also applies if you previously owned a main residence that you sold before buying the new one, even if there is a gap between the two transactions. The key test is whether you owned more than one residential property at the end of the day of your new purchase.

Worked examples: SDLT when selling and buying

The following examples illustrate the most common scenarios for someone selling one property and purchasing another in 2026.

Example 1: Sale and purchase complete on the same day

You sell your current home for £300,000 and buy a new home for £400,000. Both complete on the same day.

Because both transactions complete on the same day and you are replacing your main residence, the higher rate surcharge does not apply. You pay the standard rates only.

Example 2: You buy before your sale completes

You buy a new home for £400,000 but your existing property has not yet sold. At completion, you own two residential properties.

The difference is substantial: £30,000 at the higher rates compared with £10,000 at the standard rates — an extra £20,000. If you sell your old property within 36 months, you can claim back the £20,000 surcharge from HMRC. But you need the cash to pay it upfront, which can significantly affect your finances in the short term.

Example 3: Buying a lower-value property

You are downsizing and purchase a property for £200,000 on the same day you sell your existing home.

Even when downsizing, you still pay SDLT on the new property. The only way to avoid stamp duty entirely is to purchase below the £125,000 nil-rate threshold. For a full picture of all the costs involved in moving, see our guide to who pays for what in a house sale.

The 36-month window and how refunds work

If you end up paying the higher rate surcharge because you bought before selling, HMRC provides a 36-month (three-year) window to sell your previous main residence and claim the surcharge back. The rules, set out in HMRC's guidance on additional residential properties, work as follows:

1. You must sell your previous main residence within 36 months of completing on the new property.
2. The old property must have been your main residence at some point during the period you owned both.
3. You must submit your refund claim within 12 months of the sale of the old property, or within 12 months of the filing date for the SDLT return on the new purchase, whichever is later.
4. Claims can be made online via the GOV.UK SDLT service or by letter to HMRC.
5. HMRC typically processes refunds within 15 working days.

Important: The 36-month clock starts from the date of completion on the new property, not from the date of exchange or the date you moved in. If the deadline passes without a sale, the surcharge becomes permanent and cannot be reclaimed.

What happens if completion dates do not align

In a property chain, the aim is for all transactions to complete on the same day. In practice, this does not always happen. Delays with mortgage offers, search results, or enquiries can push completion dates out of sync. When you are arranging a simultaneous exchange and completion, the risk of misalignment is particularly acute.

If your purchase completes before your sale:

• You will temporarily own two properties and must pay the higher rate surcharge on the purchase.
• Your solicitor will calculate and submit the SDLT return at the higher rates.
• Once your sale completes (within 36 months), you can apply to HMRC for a refund of the surcharge element.
• You need to have the additional funds available at completion — your solicitor will require them before they can complete.

If your sale completes before your purchase, there is no issue. You will own zero properties when you buy the new one, so the higher rate surcharge does not arise.

Stamp duty in property chains

Each buyer in a property chain pays SDLT independently on their own purchase. The chain structure does not change the amount of tax anyone owes. What matters is whether each individual buyer owns more than one property at the point they complete.

In a straightforward chain where everyone completes on the same day:

• The first-time buyer at the bottom pays SDLT at the first-time buyer rates (nil rate up to £300,000 on properties up to £500,000).
• Each seller-buyer in the middle pays standard SDLT rates on their purchase, with no surcharge because they are replacing their main residence on the same day.
• The buyer at the top of the chain pays standard rates if it is their only property, or the higher rates if they already own another.

Chain breaks and delays are one of the biggest risks in conveyancing. If one link in the chain fails to complete on time, it can push everyone else's dates and trigger surcharge liabilities. This is another reason why getting your legal paperwork prepared early is so important — it reduces the chance of delays that could cost you thousands in additional stamp duty.

SDLT for different property types

The type of property you are buying can affect your SDLT liability in specific situations:

• Freehold houses: Standard SDLT rates apply. The higher rate surcharge applies only if you own another property at completion.
• Leasehold flats: SDLT is calculated on the purchase price in the same way as freehold. However, if you are granted a new lease with a substantial premium, different rules may apply to the rent element.
• New-build properties: Standard rates apply. Some developers offer stamp duty contributions as part of their incentive packages — these can reduce the cost but do not change the underlying tax calculation, which is based on the full market value.
• Mixed-use properties: If a property includes both residential and non-residential elements (for example, a flat above a shop), non-residential SDLT rates apply. These are lower than residential rates and the higher rate surcharge does not apply.
• Properties under £40,000: A property purchased for less than £40,000 does not attract SDLT and is not counted when assessing whether the higher rate surcharge applies to other purchases.

Stamp duty in Scotland and Wales

If your new property is in Scotland or Wales, different taxes apply. SDLT only covers England and Northern Ireland.

Scotland: Land and Buildings Transaction Tax (LBTT)

Scotland's equivalent of stamp duty is administered by Revenue Scotland. The Additional Dwelling Supplement (ADS) for second properties is 8% of the total purchase price — significantly higher than the 5% surcharge in England. The ADS can be reclaimed if you sell your previous main residence within 18 months (not 36 months as in England).

Wales: Land Transaction Tax (LTT)

Wales uses Land Transaction Tax, administered by the Welsh Revenue Authority. The higher rates surcharge for additional properties in Wales is 6%. The refund window for selling a previous main residence is 36 months, the same as England.

Key point: The tax you pay depends on where the property you are buying is located, not where you currently live. If you are selling in England and buying in Scotland, you pay LBTT, not SDLT.

How to reduce your stamp duty bill

While stamp duty rates are set by law and cannot be negotiated, there are legitimate strategies to minimise your liability:

1. Align completion dates. The single most effective step is ensuring your sale and purchase complete on the same day. This avoids the higher rate surcharge entirely. Work with your solicitor to coordinate dates across the chain.
2. Sell before you buy. If alignment is not possible, selling your current home first means you will own zero properties when you purchase, so the surcharge does not apply. You may need temporary rental accommodation, but the savings can outweigh the cost.
3. Claim the refund promptly. If you do pay the surcharge, apply for your refund as soon as you sell the old property. Do not wait — the 12-month claim window can expire faster than you expect.
4. Consider the purchase price carefully. SDLT is calculated on exact thresholds. A purchase price just above a threshold band costs disproportionately more in tax than one just below it. Your solicitor can confirm the precise SDLT due at different price points.
5. Check for mixed-use classification. If the property has genuine non-residential elements, non-residential SDLT rates may apply, which are lower and do not carry the higher rate surcharge. This is a specialist area — take professional advice.

Budgeting for stamp duty in your move

Stamp duty is one of the largest costs of buying a home, and it must be paid within 14 days of completion. Your solicitor will typically submit the SDLT return and payment on your behalf from the completion funds.

When budgeting for a simultaneous sale and purchase, factor in:

• The standard SDLT on your purchase (see the rate tables above).
• The possibility of the higher rate surcharge if completion dates slip — ensure you have contingency funds or a plan to cover the extra 5%.
• Solicitor fees, estate agent fees, and all other costs on the selling side — our complete guide to selling costs breaks these down.
• The total cash you need at completion, including your deposit on the new property, SDLT, and any fees your solicitor is collecting.

Use the GOV.UK SDLT calculator to get an accurate figure for your specific purchase price. Your solicitor will confirm the exact amount before completion.

Sources and further reading

• Stamp Duty Land Tax — Residential Property Rates (GOV.UK)
• SDLT: Buying an Additional Residential Property (GOV.UK / HMRC)
• SDLT Reliefs and Exemptions (GOV.UK)
• Apply for a Repayment of the Higher Rates for Additional Properties (GOV.UK / HMRC)
• Land and Buildings Transaction Tax (Revenue Scotland)
• Land Transaction Tax Rates (Welsh Revenue Authority)
• Stamp Duty Land Tax Overview (GOV.UK)

Frequently asked questions