Step one: the online account and what to have ready
The standard route is HMRC's online Capital Gains Tax on UK property account. You need a Government Gateway user ID, and non-residents can create one even without a National Insurance number. Gather the figures before completion rather than after: the completion date, the sale proceeds, the original cost or the 5 April 2015 value if you owned the property before that date, improvement costs, and the buying and selling fees. For residential property owned before 6 April 2015 there are three computation methods, and an election out of the default rebasing is irrevocable for that disposal, so compare all three first. An agent can file for you through an agent-linked account, which is often the fastest route from overseas. If you cannot report online, HMRC will issue a paper form on request, but build in postal time because the deadline does not move. Our 60-day CGT guide for non-residents has three worked examples.
Step two: pay within the same window
Filing and paying are two halves of one deadline. Once the return is submitted, HMRC issues a 14-character payment reference starting with X, and you pay using that reference within the same 60 days from completion. A return filed on day 59 with the tax paid on day 70 still attracts interest on the late payment, so treat payment as part of the conveyancing timetable, not an afterthought. For 2026/27, residential gains are taxed at 18% within your unused basic rate band and 24% above it, after the £3,000 annual exempt amount. Because the tax year is usually not over at completion, you estimate your income for the year in the 60-day return; if the estimate proves wrong, Self Assessment corrects it later. Private Residence Relief, including the final 9 months of ownership and the 90-day occupation test for years abroad, is applied in the same computation. Our CGT for non-residents guide covers the regime end to end.
Nil gain still needs a return, and Self Assessment afterwards
The trap unique to non-residents is the nil-gain filing duty. A UK resident only files the 60-day return when tax is actually payable; a non-resident must report every disposal of UK land, including a loss and a sale fully covered by Private Residence Relief. Skipping the return because there is nothing to pay is the most common mistake we see sellers abroad make, and it costs an automatic £100 penalty, then £300 or 5% of the tax, whichever is higher, at 6 months and again at 12 months, with interest on any late-paid tax. The 60-day return does not replace your annual filing either: if you are in Self Assessment, the disposal goes on the Capital Gains pages too, with credit for the tax already paid. Whether you are non-resident for the year is decided by the Statutory Residence Test, so pin that down before completion.