The UK side, explained.
The UK taxes on residence rather than nationality. That makes the threshold question a factual one, and the answer decides everything that follows.
Residence is a test, not a feeling
The statutory residence test decides your UK position on counted days and defined ties, not on where you consider home to be. It runs in a fixed order: automatic overseas tests first, then automatic UK tests, then the sufficient-ties test.
Because it is mechanical, it is also plannable. Knowing where you sit before a tax year ends is far more useful than establishing it afterwards, particularly in a year you move.
Not everyone has to file
If all your UK income runs through PAYE and nothing else is going on, you may have no Self Assessment requirement at all. Plenty of people file who need not, and plenty who should file assume PAYE has covered it.
You will generally need to file with self-employment or rental income, untaxed foreign income, capital gains to report, higher-rate liability, or where HMRC has issued a notice to file.
- Self-employment or rental income
- Untaxed foreign income or gains
- Higher-rate or additional-rate liability
- A notice to file issued by HMRC
Where the US changes the answer
Several things that are genuinely tax-free in the UK are not tax-free to the IRS. An ISA is the clearest case: no US recognition of the wrapper, and most of what sits inside one is a PFIC.
The same applies to a pension's tax-free lump sum and to Private Residence Relief on a home sale. Where you have US exposure, the UK-optimal choice and the overall-optimal choice are frequently not the same thing.
Last reviewed . Thresholds and rates change annually — check figures against the current tax year before relying on them.
Have UK filings and US exposure?
We prepare both together so the reliefs are claimed in the right country, in the right order. Tell us your position.