The stamp duty surcharge on a second property is 5 points, not 3

If you are budgeting a buy-to-let purchase in England or Northern Ireland from a figure you looked up online, check the surcharge rate first. The additional dwellings surcharge is 5 percentage points, not 3, for transactions with an effective date on or after 31 October 2024. The single rate for companies and other non-natural persons buying a dwelling over £500,000 is 17%, not 15%, from the same date.

Both figures are still circulating in their old form on calculators, in blog posts and in spreadsheets that nobody has revisited. On a £300,000 purchase the first error is £6,000. On a £600,000 purchase the second one can be tens of thousands. This article sets out the current position and shows the arithmetic.

The higher rates, band by band

Both tables apply from 1 April 2025. The surcharge bites where the additional property costs £40,000 or more, and it applies to the whole price once that threshold is crossed, not just to the excess.

An illustrative example: a £300,000 buy-to-let

Take a landlord in England buying a £300,000 house as an additional dwelling. The figures are illustrative.

• 5% on the first £125,000 = £6,250
• 7% on the next £125,000 = £8,750
• 10% on the remaining £50,000 = £5,000
• Total: £20,000

On the old 3-point surcharge the same purchase produced £3,750 plus £6,250 plus £4,000 = £14,000. The difference is £6,000, which is exactly 2% of the price, because the surcharge applies across every band. A landlord who budgeted from an out-of-date calculator is £6,000 short at completion, and it is due within 14 days.

If you are not UK resident, add two more points

The non-UK resident surcharge is 2 percentage points, in force since 1 April 2021. The test is presence: you are treated as non-resident for this purpose if you were not in the UK for at least 183 days in the 12 months before the purchase. It stacks on top of all other residential rates, including the additional dwellings rates.

On the same £300,000 purchase, that adds 2% of £300,000 = £6,000, taking the bill from £20,000 to £26,000. A non-resident landlord buying a £300,000 second property therefore pays 8.67% of the price in stamp duty before they have collected a penny of rent.

Companies: the 17% flat rate and the reliefs that usually escape it

Two separate rules apply to a company buying residential property, and they are frequently conflated.

First, the higher rates apply to any residential purchase by a company of £40,000 or more. There is no equivalent of the "first property" exception that individuals get.

Second, a single rate of 17% applies to a "higher threshold interest" — a single dwelling with chargeable consideration over £500,000, or linked transactions aggregating above £500,000 — bought by a non-natural person, from 31 October 2024. Non-natural persons are companies, partnerships with one or more corporate partners, and collective investment schemes.

The 17% rate is what most people have heard of and it is what most genuine buy-to-let companies do not pay, because reliefs take them back onto the ordinary higher rates. The reliefs include a property rental business, a property developer or trader, property made available to the public in a trade, a financial institution acquiring in the course of lending, occupation by employees of the purchaser, a farmhouse, and a qualifying housing co-operative. All of them are subject to clawback if the qualifying condition stops being met.

Illustratively, on a £600,000 single dwelling: the 17% flat rate produces £102,000. The ordinary higher rates produce £6,250 plus £8,750 plus 10% of £350,000 = £50,000. The relief is worth £52,000 on one purchase — which is why whether it applies, and whether it survives clawback, is a question to settle before exchange rather than after.

Wales and Scotland have their own taxes

Stamp Duty Land Tax applies in England and Northern Ireland only.

Wales has Land Transaction Tax. Its higher residential rates, from 11 December 2024, run 5% to £180,000, 8.5% to £250,000, 10% to £400,000, 12.5% to £750,000, 15% to £1.5m and 17% above. Note the different band edges — and that Wales has no first-time buyer relief at all.

Scotland has Land and Buildings Transaction Tax, with an Additional Dwelling Supplement of 8% for transactions on or after 5 December 2024 where the consideration is £40,000 or more. The ADS replacement window is 36 months for transactions from 1 April 2024, up from 18 months.

Applying an English figure to a Welsh or Scottish purchase produces a wrong answer every time, and the direction of the error is not consistent.

What is worth checking before you exchange

• Recalculate anything budgeted before 31 October 2024, and anything produced by a calculator you have not verified. Two points on the whole price is real money.
• Check whether contracts were exchanged before 31 October 2024. Transitional rules may apply where a contract was exchanged before that date and completed on or after it.
• If a company is buying, establish which relief from the 17% rate you are relying on and what would trigger clawback.
• Count your days if you have been abroad. 183 days in the 12 months before purchase is the test, and it is not the same as your income tax residence position.
• Diarise the refund window if you have bought before selling a former main home.

The stamp duty calculator covers all three regimes with the surcharge, the non-resident points and the corporate rate. If the purchase is part of a wider question about holding property in a company, the incorporation guide sets out where stamp duty on market value comes in, and accountants for property companies and SPVs explains what we do for company landlords. Nothing here is advice on a specific transaction, and the figures should be confirmed on the actual contract before you rely on them.