Every deadline that matters, on both sides.
Two tax years that don't align — calendar year for the IRS, 6 April to 5 April for HMRC — and a lattice of deadlines between them.
The dates worth diarising
US side: 15 April is payment day for everyone, but expats get an automatic filing extension to 15 June and can extend to 15 October; the FBAR follows the return with its own automatic October extension. Estimated taxes fall quarterly. UK side: 31 January closes online Self Assessment and opens payments on account, with a second instalment on 31 July — and residential property sales demand a CGT return within 60 days of completion.
The trap is the mismatch: US tax on UK income can fall due before HMRC has even finished the year that created it. Credit planning lives in that gap.
- US: 15 April pay / 15 June expat file / 15 October extended
- UK: 31 January file & pay, 31 July second instalment
- UK property sales: 60-day CGT return, easily missed
Every date, ordered from today
Next up: UK paper Self Assessment deadline — in 12 days.
| Date | System | Deadline |
|---|---|---|
| 31 Oct ← | UK | UK paper Self Assessment deadline |
| 15 Dec | US | US further expat extension (by request) ends |
| 15 Jan | US | US Q4 estimated tax payment |
| 31 Jan | UK | UK Self Assessment online filing + payment, first payment on account |
| 5 Apr | UK | UK tax year ends |
| 15 Apr | US | US tax payment due for everyone; Q1 estimate; FBAR nominal deadline (auto-extends to 15 Oct) |
| 15 Jun | US | US filing deadline for taxpayers abroad (automatic 2-month extension); Q2 estimate |
| 31 Jul | UK | UK second payment on account |
| 15 Sept | US | US Q3 estimated tax payment |
| 5 Oct | UK | UK deadline to register for Self Assessment (new filers) |
| 15 Oct | US | US extended filing deadline; FBAR automatic extension ends |
Event-based deadlines sit outside this calendar: UK residential property sales need a CGT return within 60 days of completion, and new US business entities have their own first-year dates.
Questions we get about this
File as soon as possible. Penalties generally accrue with time, so a late filing is materially better than a later one.
If several years are outstanding, stop and take advice before filing - the route you choose matters more than speed.
Treat it as a starting point. If it says an obligation applies, the next question is what the filing actually involves and whether earlier years are affected.
If it says nothing applies, it is worth re-running whenever your circumstances change - a move, a property, a new account.
The US tax year is the calendar year; the UK runs 6 April to 5 April. Income in one UK year can straddle two US years as a result.
It is also why the order the two returns are prepared in genuinely affects the credits available.
US filers abroad get an automatic extension to mid-June without asking, and can extend further to mid-October on request.
It is an extension to file, not to pay - interest still runs on anything owed from the April date.
They are the general pattern rather than advice for a specific year. Deadlines shift for weekends and public holidays, and extension rules change.
Check against current IRS and HMRC guidance if a deadline is close, or ask us.
Related pages
- Free tool
Annual exchange rate lookup
Look up the annual average exchange rates used to convert UK income and balances for a US return, with the source each published figure comes from.
- Pillar guide
Tax specialists for US and UK
What US and UK tax specialists handle that a general accountant does not: residence tests, treaty relief, FBAR, PFICs, pensions, property and catch-up filings.
- Service
UK Self Assessment
UK Self Assessment prepared alongside your US return: residence, remittance planning, and reliefs claimed in the right country.
- Service
Form 4868 (1040 extension)
Form 4868 explained: extending the 1040 filing deadline to 15 October, the automatic expat extension to 15 June, Form 2350, and interest on unpaid tax.
- Pillar guide
Accountants for US and UK
How to choose accountants for US and UK tax: what each credential permits, how to verify it, what drives the fee, and when you do not need a specialist.
- Glossary
FBAR: definition
The Foreign Bank Account Report — FinCEN Form 114 — and its $10,000 aggregate trigger.
Further reading
- The October 15 deadline: your last stop for this year's US filings
The season ends here: extended returns and the FBAR land on the same day. What must be in, what can wait, and what missing it actually costs.
- The UK tax year: why 6 April runs your British filings
Britain counts its tax year from 6 April, America from 1 January. That single mismatch touches every figure a cross-border family reports.
- Payments on account: the UK tax bill that arrives twice
Two advance instalments, a 150% first-year surprise, and a reduction lever most people never pull. The advance-payment system, explained properly.
Last reviewed . Thresholds and rates change annually — check figures against the current tax year before relying on them.
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