Property and gains, reported to two authorities on different rules.
Selling a home, letting a flat, or holding investments across borders means two sets of gain calculations, different reliefs, different dates, and a currency conversion that can create profit neither country's rules feel intuitive about.
The exchange rate is part of your gain
The IRS measures your gain in dollars: purchase price at the historic rate, sale price at today's. A London home that barely moved in sterling can show a six-figure dollar gain, and paying off a sterling mortgage can generate a separate, taxable currency gain on the debt itself.
UK principal-residence relief and the US $250k/$500k exclusion overlap imperfectly, so the timing of a sale decides how much of the gain survives into tax.
- US and UK gain calculations, including currency effects
- UK 60-day CGT reporting for residential sales
- Rental income reported correctly on both sides
Landlords file in both countries
Rental profit is computed differently on each return, depreciation is mandatory for the IRS and non-existent for HMRC, interest relief differs, and the non-resident landlord scheme adds withholding. We keep the two computations consistent and the credits flowing the right way.
Records first, then the two returns
The return is only as good as the records behind it: purchase documents and improvement costs, the dates the property was your main home on each side, and the exchange rates on the day you bought and the day you sold. We gather those early, because the UK deadline leaves little time after completion.
Once the sale completes we handle the 60-day UK return, the US gain with its currency layer and depreciation recapture, and the credit claim that stops the same gain being taxed twice.
- Main-residence relief calculated on both sides
- Purchase and improvement records reconstructed
- 60-day UK return plus the US gain, coordinated
US-UK double taxation and the treaty
How the treaty, foreign tax credits and the earned income exclusion stop the same income being taxed twice.
Questions we are asked most
The ones that come up in almost every first conversation about property & capital gains.
UK residential property disposals that produce a gain require a standalone return and payment within 60 days of completion.
It sits apart from Self Assessment, and missing it attracts penalties even where the annual return is filed on time.
Yes. Periods of letting affect UK relief on a main residence, and on the US side depreciation taken during the rental period is recaptured on sale.
Depreciation is required rather than optional in the US, so not having claimed it does not avoid the recapture.
Losses on a main residence are generally not deductible in either system, though investment property losses can be.
Currency movement can also mean a loss in one currency and a gain in the other, which is worth calculating before assuming there is nothing to report.
No. The US runs its own calculation on the same sale, and its principal residence exclusion is capped well below full UK relief.
Anything above that cap is a taxable gain to the IRS even where HMRC takes nothing.
The US computes the gain in dollars, using the exchange rate at purchase and at sale. A property that barely moved in sterling can show a substantial dollar gain purely on currency movement.
That gain is taxable even though in your own currency you made almost nothing.
It can, on the same logic. A foreign-currency mortgage repaid when rates have moved can produce a separate dollar-denominated gain.
It surprises people because nothing about the transaction feels like a profit.
Related services
Most positions touch more than one of these. We prepare them from the same file.
Selling a property this year?
There is a 60-day UK clock and a separate US calculation in dollars. We will tell you what both come to before you complete.