US & UK tax deadlines
Cross-border filers live on two calendars. These are the recurring dates that matter — when a date falls on a weekend or holiday it usually moves to the next business day.
United States (IRS & FinCEN)
The US tax year is the calendar year.
| Date | What happens |
|---|---|
| 15 April | US federal return and payment normally due; any tax owed accrues interest after this date even if you file later. FBAR is also due, with an automatic extension to 15 October. |
| 15 June | Automatic two-month filing extension for taxpayers living outside the US on the regular due date — file by now or request more time. |
| 15 October | Extended filing deadline (Form 4868 request) and the automatically extended FBAR deadline. |
| 15 December | A further discretionary filing extension is possible for taxpayers abroad, by written request to the IRS. |
| Quarterly | US estimated tax instalments (normally 15 April, 15 June, 15 September, 15 January) if you expect to owe US tax. |
United Kingdom (HMRC)
The UK tax year runs 6 April to 5 April.
| Date | What happens |
|---|---|
| 5 April | The UK tax year ends (the new tax year starts 6 April). |
| 5 October | Deadline to register for Self Assessment if you need to file for the tax year that ended in April. |
| 31 October | Paper Self Assessment filing deadline. |
| 31 January | Online Self Assessment filing deadline, balancing payment for the previous tax year, and the first payment on account for the current one. |
| 31 July | Second payment on account, where payments on account apply. |
| 60 days | UK residential property disposals with tax due must be reported and paid within 60 days of completion. |
An extension to file is not an extension to pay.
In both systems, interest generally runs from the original payment date regardless of filing extensions. Cross-border planning often turns on paying the right country first — timing affects foreign tax credits in the other return.
General information only — exact dates shift with weekends and holidays, and your circumstances may change what applies. Check irs.gov and gov.uk for the current year, or ask us.
Racing a deadline in either country?
Extensions, estimated payments and catch-up filings are routine for us — but they work far better started early. Tell us where you stand.
Or call +44 20 8064 3580 — we’ll tell you honestly whether you need help.