US Citizen Buying a House in the UK: Tax, Stamp Duty, Mortgages and Currency Gains

A US citizen buying a house in the UK pays the same Stamp Duty Land Tax as any other buyer, but the tax depends on homes owned anywhere in the world, so an American who has ever owned a US home loses first-time buyer relief and may pay a 5% surcharge. The US side then starts on completion day: the home gets a dollar cost basis, the sterling mortgage becomes a currency position, and both matter years later when you sell or repay.

This guide is for Americans buying a first home in the UK, whether they have lived here for years or are about to move. It covers the UK purchase taxes first, then the US tax consequences that most buyers only meet when they sell. Rates and thresholds below are as published on GOV.UK and IRS.gov on 23 October 2026. The UK Autumn Budget is due on 28 October 2026, so check the GOV.UK rates page again if you complete after that date.

What tax does a US citizen pay when buying a house in the UK?

The main UK tax on buying a home is a one-off purchase tax. In England and Northern Ireland it is Stamp Duty Land Tax (SDLT). Scotland charges Land and Buildings Transaction Tax and Wales charges Land Transaction Tax, each with its own rates and reliefs, so a purchase in Scotland or Wales needs the Revenue Scotland or Welsh Revenue Authority rules instead. US citizenship itself makes no difference to the rate.

Three facts about you decide the SDLT bill: whether you have ever owned a home anywhere in the world, whether you will own any other home when the purchase completes, and how many days you spent in the UK in the 12 months before completion. Your conveyancer will usually file the SDLT return and pay the tax for you. GOV.UK says the return and payment are due within 14 days of completion.

The standard rates

The GOV.UK residential rates page sets these bands for a buyer of a single residential property in England or Northern Ireland. Each rate applies only to the slice of the price inside its band.

Portion of the price	Standard rate	First-time buyer rate (price £500,000 or less)
Up to £125,000	0%	0% up to £300,000
£125,001 to £250,000	2%	0% up to £300,000
£250,001 to £925,000	5%	5% from £300,001 to £500,000
£925,001 to £1.5 million	10%	Relief not available
Above £1.5 million	12%	Relief not available

Two surcharges sit on top. A buyer who will own more than one residential property usually pays 5% extra under the higher rates for additional properties. A buyer who is not UK resident for SDLT purposes usually pays a 2% surcharge in England and Northern Ireland. Both can apply to the same purchase.

Can an American who owned a US home claim first-time buyer relief?

No. First-time buyer relief in SDLT is a worldwide test, and an American who has ever owned a home in the United States fails it. HMRC's manual at SDLTM29845 says the buyer must never have acquired a major interest in a dwelling, or an equivalent interest in land, anywhere in the world, regardless of its value.

This catches people who do not think of themselves as former homeowners. A condo bought in your twenties and sold before moving, or a share of a house held with a former partner, both count. Joint buyers must each pass the test, so one partner's old US home removes the relief for both. GOV.UK also says the relief is not available at all on a home costing more than £500,000.

The same worldwide reach applies to the Lifetime ISA, the UK savings account that adds a government bonus to money saved for a first home. GOV.UK sets the conditions on its Lifetime ISA withdrawal page: you must be a first-time buyer, the home must cost £450,000 or less, you must buy with a mortgage at least 12 months after your first payment, and the money goes to your conveyancer. Other withdrawals carry a 25% charge. For a US citizen there is a second problem: the US gives an ISA no tax-free status, and an ISA invested in UK funds can hold PFICs, which our guide to ISAs and PFIC rules for US citizens explains.

When do the 5% and 2% surcharges apply to Americans?

The 5% higher rates catch Americans who keep their US home. GOV.UK guidance on buying an additional residential property says the higher rates apply if the new home will not be the only residential property worth £40,000 or more that you own, or part own, anywhere in the world at the end of the day you buy. A house in Ohio that you are renting out while you live in London counts.

Spouses and civil partners are treated as buying together. If your spouse still owns a US home, the higher rates can apply to the whole purchase even if only your name is on the UK title. The main exception is replacing your main residence: if the US house was your main home and it is sold within the time allowed, the extra 5% either does not apply or can be reclaimed. The residential rates page describes the 36-month window.

The 2% non-resident surcharge depends on days, not citizenship or visa status. GOV.UK's guidance on rates for non-UK residents says an individual is non-resident if they were not present in the UK for at least 183 days in the 12 months before the purchase. This test is separate from the statutory residence test used for income tax, so an American who has just moved can be UK resident for income tax and non-resident for SDLT.

The non-resident surcharge has three useful rules:

• Spouse rule. If your spouse or civil partner is UK resident for the purchase and you are not separated, you are both treated as UK resident.
• Refund. An individual who is in the UK for at least 183 days in any continuous 365-day period, inside a window running from 364 days before to 365 days after completion, can reclaim the 2% by amending the return within two years of completion.
• Crown employment. Days abroad in Crown employment can count as UK days, but only when the relief is claimed on the return.

A worked example: one house, four stamp duty bills

Illustrative example: an American buys a £450,000 home in Manchester to live in. The figures use the GOV.UK rates for England published on 23 October 2026. They are not advice for your purchase.

1. Never owned a home anywhere, UK resident for SDLT. First-time buyer relief applies: 0% on the first £300,000 and 5% on the next £150,000, so SDLT is £7,500.
2. Sold a US condo years ago, UK resident for SDLT. No first-time buyer relief. Standard rates apply: 0% on £125,000, 2% on £125,000 (£2,500) and 5% on £200,000 (£10,000), so SDLT is £12,500.
3. Still owns a US rental house, UK resident for SDLT. The 5% higher rates apply on top of the standard rates across the whole price: £12,500 plus £22,500, so SDLT is £35,000.
4. Still owns the US rental and moved to the UK four months ago. Add the 2% non-resident surcharge on the whole price, another £9,000, so SDLT is £44,000 at completion. The £9,000 can be reclaimed if the buyer later meets the 183-day test inside the window.

The gap between the first and last lines is £36,500 on the same house. The facts that drive it are all fixed before exchange, which is why the order of selling the US home, moving and completing is worth planning.

US tax on a UK home: the dollar basis and the mortgage interest deduction

The IRS treats a UK home as property bought in a foreign currency, and every US figure about it is in dollars. The IRS page on foreign currency and exchange rates says to use the exchange rate prevailing when you pay or receive an amount. In practice the purchase price is translated at the rate on the completion date, and that dollar figure is the starting cost basis. Our note on the IRS exchange rate for GBP covers which rates are acceptable.

SDLT is not deductible on a US return. IRS Publication 530 says you cannot deduct foreign taxes you paid on real estate, and tells a buyer who pays transfer taxes to include them in the cost basis of the property. Legal fees, surveys and recording fees are added to basis too. Mortgage arrangement fees and other loan charges are not.

Mortgage interest on a UK home can be deductible. IRS Publication 936 allows a deduction for interest on debt used to buy a main or second home, and its definition of a qualified home does not require the home to be in the United States. The 2025 publication limits the deduction to interest on $750,000 of acquisition debt taken out after 15 December 2017, or $375,000 if married filing separately. The deduction only helps if you itemize on Schedule A, and many Americans in the UK take the standard deduction or have no US tax left after foreign tax credits. A UK lender will not issue Form 1098, so keep the annual mortgage statements.

The currency gain trap on a sterling mortgage

A sterling mortgage is a second US transaction, separate from the house, and repaying it can create taxable income. If you borrow pounds when they are worth more dollars and repay them when they are worth fewer, the US sees a gain on the loan. Section 988(e) of the Internal Revenue Code ignores currency gain on an individual's personal transaction only when that gain is $200 or less.

Illustrative example: a buyer takes a £300,000 mortgage when £1 buys $1.30, a dollar value of $390,000. Years later the remaining balance is repaid on a sale when £1 buys $1.20. Repaying £300,000 now costs $360,000, so the buyer has a $30,000 currency gain on the loan. The exchange rates are hypothetical.

That gain is taxable even if the house itself sells at a loss. The reverse is not symmetrical: a currency loss on a mortgage for your own home is a personal loss and is not deductible. The UK sees no gain at all because the loan was in pounds, so there is usually no UK tax to credit against the US bill. Our guide to section 988 currency gain covers the rules, the IRS ruling behind them and what remortgaging does.

Buying with a non-US spouse and other US reporting

Title matters for an American married to a non-American. If the US spouse pays for a home put in joint names, the non-US spouse's share can be a gift for US gift tax. The unlimited marital deduction does not apply to gifts to a spouse who is not a US citizen. Instead, the IRS gift tax FAQs set an annual exclusion of $194,000 for 2026 for present-interest gifts to a non-citizen spouse. A deposit plus a share of the price can exceed it, so plan ownership with our guide to tax planning for US/UK mixed couples, and our gift tax return service can file Form 709 where needed.

A UK home owned in your own name does not go on an FBAR or Form 8938. The IRS comparison of the two forms says foreign real estate held directly is reportable on neither. The money around the purchase is reportable: a UK savings account holding a deposit counts towards the FBAR threshold of $10,000 in aggregate at any time in the year. See our guide to FBAR requirements for expats. Buying through a UK company changes the US picture completely, as our post on a UK property company for a US citizen explains.

What US citizens buying a house in the UK often get wrong

• Assuming they are first-time buyers. A US home owned years ago, or a share of one, ends first-time buyer relief.
• Completing before the US house is sold. The 5% higher rates are tested at the end of the completion day, and the spouse rule can bring a partner's US home into the count.
• Forgetting the 2% refund. A recent arrival who later meets the 183-day test can reclaim the surcharge, but only within two years of completion.
• Recording the basis in pounds. The US gain on a future sale is measured in dollars, so the completion-date rate and the SDLT paid need to be on file now.
• Ignoring the mortgage. The home sale exclusion of up to $250,000, or $500,000 on a joint return, under IRS Topic 701 covers gain on the house, not currency gain on repaying the loan.

A checklist before you exchange contracts

1. List every residential property you and your spouse have ever owned, anywhere in the world, with dates.
2. Count your UK days in the 12 months before the planned completion date.
3. Decide whether the US home will be sold before completion, and check the replacement-of-main-residence timing.
4. Agree with your spouse whose name goes on the title and who pays, and check the US gift tax position.
5. Record the completion-date exchange rate, the price, the SDLT and the legal fees for your US basis.
6. Keep the mortgage offer and annual statements for the interest deduction and the future currency gain calculation.

US/UK Cross Border Tax is a team of US CPAs and UK tax advisers working as one team, with offices in London, Manchester, New York and San Francisco. Our tax advice for US citizens buying a house in the UK covers the SDLT position and the US basis together. See how we help Americans living in the UK with the rest of their US and UK filings. If you are about to buy, talk to us before you exchange.