Form 4868: buying filing time without buying penalties.
Cross-border returns wait on UK figures that don't exist in April, so extensions are routine practice rather than a warning sign. The craft is in the sequence: extending the filing while managing the payment, because interest never waits.
Figures relate to tax year 2025 (US) · 2025-26 (UK)
Three deadlines, one calendar
Americans abroad get an automatic two-month extension to mid-June — no form, just a statement with the return. Form 4868 extends filing to mid-October for anyone, and a further discretionary extension to mid-December exists by letter for taxpayers abroad who need it.
None of that moves the payment date: tax is due in April, and interest accrues from then on any balance. Late-payment penalties are softened for those abroad until June, but interest is universal.
- Automatic June 15 filing extension when abroad
- Form 4868 — extension to October 15
- Discretionary December 15 extension by letter
- Payment still due April 15; interest runs regardless
Extend with a payment attached
A good extension carries an estimate: pay the projected balance with the 4868 and the eventual return settles pennies, not penalties. We build that estimate from the UK data available in spring — payslips, prior-year patterns — so October filings arrive without an interest bill trailing them.
FBARs extend automatically to October with no form at all, and state extensions follow their own rules — each is tracked on its own line of the calendar.
Primary sources
Official guidance from the IRS, FinCEN and GOV.UK. Thresholds and rates on those pages are updated annually — check the current tax year before relying on a figure.
Questions, Answered.
What clients ask about form 4868 — 1040 extension
Does an extension increase audit risk?
No. Extensions are procedural and millions file them; a complete, accurate October return serves you far better than a rushed April one. Cross-border returns extended for UK figures are entirely ordinary.
I can't pay by April. Should I still extend?
Yes — the failure-to-file penalty dwarfs the failure-to-pay penalty. Extend, pay what you can, and arrange the rest; the worst combination is missing the filing because the payment wasn't ready.
Does Form 4868 cover my state return and FBAR too?
The FBAR extends automatically to October with no request. States vary — some honour the federal extension, some want their own form, and some want payment regardless. We map each state you touch.
Is there a penalty for filing Form 4868?
No — the extension is automatic and penalty-free by itself. Penalties attach to paying late, not extending: interest runs from April on any unpaid balance, which is why we extend with a payment rather than instead of one.
Can I still contribute to an IRA if I extend my return?
IRA contributions for a tax year are due by the April deadline regardless of extensions — extending the return doesn't extend the contribution window. SEP-IRA contributions for the self-employed, by contrast, can follow the extended deadline.
Next Step.
Tell us what you hold — the scope and a fixed fee follow in writing.