Which UK tax form do I need?

Which UK tax form do I need when I leave the UK?

Direct answer: Almost everyone leaving the UK needs one form to tell HMRC: P85 if you're not in Self Assessment, or the SA109 residence pages with your return if you are — you never file both for that job. Then NRL1 (to receive UK rent gross), the NRCGT 60-day return (selling UK property) and CF83 (voluntary National Insurance) only apply if those things are true for you (gov.uk "Tax if you leave the UK"; P85 guidance; 2026/27).

The form alphabet soup makes leaving feel more complicated than it is. In reality there's a spine — tell HMRC you've gone — and a few branches that follow specific bits of your UK life out of the country: your rental, a property sale, your State Pension. This router sorts the spine from the branches and hands you a shortlist with the source next to each form. HMRC wrote the rules; we translated them, dated them, sourced them, and built the router.

P85 or Self Assessment — which one tells HMRC I've left?

Direct answer: It's decided by one thing: whether you file a Self Assessment return for the year you leave. Not in Self Assessment → form P85. In Self Assessment → report leaving on the SA109 residence pages with your tax return, and don't file a P85. The real fork is route, not paper-versus-online (gov.uk "Tax if you leave the UK"; P85 guidance; 2026/27).

gov.uk puts it plainly: if you do not usually complete a Self Assessment return you "need to fill in form P85"; if you do, you "tell HMRC you're leaving through your Self Assessment tax return. Complete the 'residence' section (form SA109) and send it by post." The P85 does three jobs at once — it notifies HMRC you've left, claims back any PAYE tax you over-paid, and gives HMRC what it needs to set your code. The SA109 does the residence job inside the return: it's where you declare you've become non-resident, claim split-year treatment, and claim the non-resident personal allowance if you're entitled.

One trap to know: the SA109 cannot go through HMRC's free online Self Assessment service. So a Self Assessment leaver files either a paper SA100 + SA109 (deadline 31 October) or uses commercial software / an agent (online, deadline 31 January). That's the kernel of truth behind "file on paper" — it's not that paper is better; it's that HMRC's free online service doesn't accept the residence pages. For a non-Self-Assessment person, by contrast, the P85 online and by post are completely equivalent. The only hard rule is procedural: if you haven't physically left the UK yet, you must print and post the P85. Read the whole thing in our P85 guide.

Do I need the SA109?

Direct answer: You need the SA109 if you have to file a Self Assessment return for the year you leave — which commonly bites for leavers who rent out UK property, are self-employed in the UK, have capital gains to report, have high income, or already file a return. The SA109 is the residence supplement to the main SA100, and it's where split-year treatment is claimed (gov.uk "Tax on your UK income if you live abroad"; SA109 notes; 2026/27).

If any of those apply, the router routes you to the SA109 and treats the P85 as not needed — you report leaving inside the return instead. On the SA109 you tick box 1 for non-residence, box 3 to claim split-year treatment (box 3.1 if more than one case applies), enter the split date in box 6, and explain the case in the free-text box 54; boxes 15/16 are where you claim the personal allowance as a non-resident. The box layout is stable, so a 2026/27 departure uses the equivalent SA109 with the same structure.

The add-on forms — NRL1, the 60-day return, and CF83

Direct answer: Three forms follow specific parts of your UK life abroad. NRL1 lets a non-resident landlord receive UK rent gross instead of having 20% deducted at source. The NRCGT 60-day return reports a UK property sale within 60 days of completion. CF83 applies to pay voluntary National Insurance abroad. Each is independent of the others (gov.uk NRLS/NRL1; CGT for non-residents; CF83; 2026/27).

• NRL1 — receive your rent gross. UK rental income stays UK-taxable however long you're away — it's not "disregarded income". Under the Non-Resident Landlord Scheme, your letting agent (or the tenant, where there's no agent) must deduct 20% tax from the rent unless HMRC approves you on NRL1 to be paid gross. Approval doesn't make the rent tax-free — it just moves collection to Self Assessment. Detail in UK rental income when living abroad and the non-resident landlord tax calculator.
• The NRCGT 60-day return — selling UK property. Non-residents are within UK capital gains tax on UK land and property (residential since 6 April 2015; all UK land and indirect disposals since 6 April 2019). You must report and pay any tax within 60 days of completion, through the UK Property Account — and crucially you must report even if there's no tax to pay or you made a loss. The annual exempt amount is £3,000 (2026/27), residential CGT is 18% / 24%, and the gain also goes on your Self Assessment return. Estimate it with the non-resident capital gains tax calculator.
• CF83 — voluntary National Insurance. National Insurance is a separate regime from income tax, so becoming non-resident doesn't switch it off. To keep building your State Pension from abroad you apply on CF83. From 6 April 2026 voluntary Class 2 for periods abroad is gone for new applicants: you pay Class 3 at £18.40/week (2026/27) and must have 10 years' UK residence or 10 qualifying years — about £767 a year more than the old Class 2 (£3.65/week). Existing payers keep transitional protection. Work it out with the voluntary National Insurance calculator.

What about a tax refund — is that a separate form?

Direct answer: No. The mid-year-leaver refund is claimed through the form you already file: the P85 claims it for non-Self-Assessment leavers, and the refund falls out of the Self Assessment return for those filing one. There's no separate refund form for the departure year (HMRC PAYE94025; gov.uk P85 guidance; 2026/27).

If you left a UK job part-way through the tax year on PAYE, you've probably overpaid, because your full £12,570 personal allowance (2026/27) was spread across a year you didn't finish working. The router signposts this and links you to the UK tax refund after leaving guide. Refunds are paid by payable order within the UK — HMRC won't wire money abroad — so keep a UK bank account or nominate a UK person until it lands, and expect a pay-then-reclaim lag. We never promise a figure or a timescale.

Is filling in these forms — and becoming non-resident — legal?

Direct answer: Yes. Filing a P85 or an SA109 is how you tell HMRC you've left and report your position openly. Non-residence is a status you qualify for in statute — the Statutory Residence Test (Finance Act 2013, Schedule 45) — not something you hide. These forms are the opposite of evasion: they put your departure on the record (HMRC RDR3; gov.uk "Tax if you leave the UK"; 2026/27).

This router doesn't file anything, store your numbers or replace the official route or a qualified adviser. It points you at the right HMRC forms and the guide for each, so you can leave the UK properly — bold about leaving, scrupulous about the tax.