Stamp Duty Surcharge on Second Homes — The 5% Additional Dwelling Supplement Explained

The Additional Dwelling Surcharge

When the government introduced the additional dwelling surcharge in 2016, it was set at 3%. In the Autumn Budget of October 2024, the Chancellor increased it to 5%, with immediate effect from 31 October 2024. This means buyers of second homes, buy-to-let properties, and holiday homes now pay SDLT at standard rates plus 5% at every band.

The surcharge applies to the entire purchase price from the first pound — there is no nil-rate band for surcharge purposes.

When Does the Surcharge Apply?

The surcharge applies if, at the end of the day of completion, you own two or more residential properties. The key test is ownership at the end of completion day, not at exchange.

You will pay the surcharge if you are:

• Buying a second home while keeping your existing main residence
• Purchasing a buy-to-let investment property
• Buying a holiday home
• Purchasing via a company or trust (companies pay the surcharge from the first residential property, not the second)

The surcharge also applies if **any** buyer in a joint purchase owns another residential property anywhere in the world — even if the other buyer is a first-time buyer.

What Counts as an "Additional Dwelling"?

A residential property is an additional dwelling if it is not replacing your previous main home. Mixed-use properties and non-residential property purchases are subject to non-residential SDLT rates rather than the surcharge.

Properties owned overseas count. If you own a property in another country, you are not a first-time buyer and your UK purchase will attract the surcharge unless it is replacing your main home.

The 36-Month Replacement Rule

The most important exception to the surcharge is the main home replacement rule. If you are selling your existing main home and buying a new one, but the timings do not align — for example you complete on your new purchase before selling the old one — you will pay the surcharge at completion. However, if you sell the previous main home within **36 months** of the new purchase completing, you can claim the 5% surcharge back in full.

This commonly happens in chain transactions where the buyer needs to complete on a purchase before their own sale has completed. The SDLT is paid upfront and reclaimed once the sale proceeds.

Joint Purchase Complications

Where one buyer in a joint purchase owns a residential property and the other does not, the surcharge applies to the entire transaction. There is no way to split the surcharge liability between buyers proportionally.

Example: Partner A owns a flat outright. Partner B has never owned property. They buy a house together for £400,000 intending to sell Partner A's flat. At completion, the surcharge applies because Partner A still owns the flat. Once the flat sells within 36 months, they can reclaim the surcharge.

Companies and Trusts

Companies pay the additional dwelling surcharge from their **first** residential property purchase. There is no equivalent of the personal "replacing your main home" relief for companies. Companies purchasing residential property priced above £500,000 may also face the Annual Tax on Enveloped Dwellings (ATED).

Worked Example

A buyer purchasing a £350,000 buy-to-let property pays:

• £0 – £125,000 @ 5% (0% standard + 5% surcharge) = £6,250
• £125,001 – £250,000 @ 7% (2% + 5%) = £8,750
• £250,001 – £350,000 @ 10% (5% + 5%) = £10,000
• **Total SDLT: £25,000**

Without the surcharge, the same purchase would cost £7,500 in SDLT. The surcharge adds £17,500.

Use our Stamp Duty Calculator at Property Passport UK to calculate the exact surcharge applicable to your purchase, with and without the surcharge, so you can compare the full cost before committing.

When to Take Advice

The surcharge rules have several edge cases — particularly around beneficial interests, trust arrangements, overseas property, and properties held in company names. If your situation is anything other than straightforward, a specialist property tax adviser or solicitor experienced in SDLT is worth consulting before exchange of contracts.