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.
Figures relate to tax year 2025 (US) · 2025-26 (UK)
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.
- Sale planning before contracts are exchanged
- 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.
Before you sell: the six-month checklist
The best property outcomes are decided before the listing goes up: gathering purchase records and improvement costs, checking how much main-residence relief survives on each side, and sometimes timing completion into the tax year where the rate or the exclusion is kinder.
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.
- Pre-sale relief and timing review
- Purchase and improvement records reconstructed
- 60-day UK return plus the US gain, coordinated
Primary sources
Official guidance from the IRS, FinCEN and GOV.UK. Thresholds and rates on those pages are updated annually — check the current tax year before relying on a figure.
Questions, Answered.
What clients ask about property & capital gains
What is the 60-day rule?
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.
Does letting the property change things?
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.
What if I sell at a loss?
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.
I get Private Residence Relief in the UK. Does that settle it?
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.
Why does currency matter?
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.
Can repaying the mortgage create a gain?
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.
Next Step.
Tell us what you hold — the scope and a fixed fee follow in writing.