Most Americans living in the UK do not need to make US estimated tax payments. Estimated tax exists for income that nobody withholds US tax from, and for a UK resident the foreign tax credit for UK income tax usually absorbs the US tax on a salary. Quarterly payments with Form 1040-ES (opens the official IRS page in a new tab) become necessary when US tax is left over after that credit: on gains inside an ISA, on rent or freelance profit where the UK charge falls short, or on taxes the credit cannot reach.
This post is for US citizens and green card holders in Britain who want to know whether the quarterly payments apply to them. It goes deeper than the estimated tax answer in our guide to US and UK tax returns for Americans in the UK. It covers who has to pay, how UK tax feeds into the figures, the safe harbour rules in plain terms, the due dates, how the underpayment penalty is worked out on Form 2210, and how to get dollars to the IRS from a UK bank.
Which Americans in the UK have to pay US estimated tax
The rules for a citizen abroad are the same as at home. You generally need to pay if you expect to owe US tax above a small IRS threshold after credits and US withholding, and that withholding will fall short of the safe harbour amounts. In practice that means income no US payer withholds from and no UK credit fully covers.
Publication 54 (opens the official IRS page in a new tab) says the test for who must pay estimated tax is the same for a US citizen or resident living abroad as for someone in the United States, and it points to Form 1040-ES for the detail. The form names the usual sources: self-employment earnings, interest, dividends, rents and alimony. For an American in Britain, that list becomes sole trader profit, buy-to-let rent, dividends from shares or funds, and capital gains. Each is taxed in the UK as well, so the real question is whether UK tax leaves anything for the US to collect.
The form also gives many people a clean exit. You do not have to pay estimated tax for the current year if you were a US citizen or resident alien for the whole of the previous year and had no tax liability for that full year, meaning your total tax was zero or you did not have to file. Because the foreign tax credit often brings the US tax on a UK salary to nil, a good number of Americans in the UK fall within that exception year after year. Our individual tax returns work checks it each time we file.
- UK sole trader or partnership profit where UK tax does not cover the US charge
- Gains and income inside a stocks and shares ISA, which the UK does not tax
- Rent from UK or US property where the UK credit falls short
- US dividends or interest with little or no US tax withheld
- The net investment income tax, which the UK credit generally does not reach
How UK tax and the foreign tax credit change the estimate
UK income tax is not US withholding. On the Form 1040-ES worksheet it enters as a credit and reduces the US tax before the payment tests are run. Where the UK tax on a type of income is at least as high as the US tax on it, the estimate for that income is usually nil.
The worksheet's credits line refers to the credits on Schedule 3 of the Form 1040, and the first of those is the foreign tax credit (opens the official IRS page in a new tab) claimed on Form 1116. The withholding line is for US income tax withheld, so PAYE deducted by a UK employer belongs in the credit, not in withholding. This matters for the arithmetic. The safe harbour targets are set by reference to your tax after credits, so a full UK credit can shrink the required payment to nothing even where the US tax before credits looks large.
The credit has limits. It works by category of income, so UK tax on a salary does not shelter an ISA gain the UK never taxed. It reduces US income tax only, so US self-employment tax at 15.3% sits outside it unless the totalization agreement (opens the official SSA page in a new tab) removes the charge, as our post on self-employment in the UK as a US citizen explains. The net investment income tax (opens the official IRS page in a new tab) appears among the other taxes on the worksheet. UK tax is generally not creditable against it under domestic law, and treaty-based claims are contested.
What the safe harbour rules mean in plain terms
You avoid the underpayment penalty if what you prepay, through US withholding and estimated payments, reaches the smaller of two targets: a set share of this year's tax, or all of last year's tax. Higher earners must cover more than last year's figure. Form 1040-ES publishes the exact shares and income limits each year.
The prior-year route is the one most people abroad rely on, because last year's tax is known and this year's is not. It only works if last year's return covered a full year. If you did not file last year, the current-year target is the only one available. Where last year's adjusted gross income passed the IRS limit, which is lower for married filing separately, the prior-year target rises above the full amount of last year's tax.
Take a US citizen employed in Manchester who has owed no US tax for years because the foreign tax credit covers her salary. In the autumn she sells funds inside her stocks and shares ISA at a large gain. The UK charges nothing, so there is no UK tax to credit, and the US taxes the gain, possibly under the fund rules our post on why the ISA worries the IRS describes. Because she was a citizen all of last year with no US tax liability, she was not required to make estimates this year and pays with her return. Next year, last year's target is this year's bill.
- Expected tax after credits and US withholding below the IRS minimum: no payments needed
- No US tax liability last year as a full-year citizen: no payments needed
- Otherwise prepay a set share of this year's tax after credits
- Or prepay all of last year's tax, with a higher target for higher earners
- Spread payments across the four dates unless income arrives unevenly
When the quarterly estimated tax payments are due
There are four instalments. The first is due on 15 April, the second on 15 June, the third in mid-September and the fourth in mid-January of the following year. If a date falls on a weekend or legal holiday, the next business day applies. The automatic filing extension for people abroad does not move these dates.
You can pay the whole estimate by the first date or in four equal amounts. Form 1040-ES also allows more than four payments, provided the total paid in each period reaches the amount required for it. The January payment can be skipped if you file the return by the start of February and pay the full balance with it.
The annualized income installment method, explained in IRS Publication 505 and claimed on Schedule AI of Form 2210, matches the required payments to when income was actually received. The form suggests it where a large change in income after the first quarter is what creates the need to pay, and says anyone using it must file Form 2210 with Schedule AI even if no penalty is owed. Our US and UK deadlines calendar lays the four dates beside the UK ones.
How the estimated tax penalty works on Form 2210
The penalty behaves like interest. The IRS works it out on each underpaid instalment, for the number of days it stays unpaid, at its published quarterly underpayment rates. It is figured on Form 2210 or calculated by the IRS, which then sends a notice. Paying the balance with the return stops it growing but does not remove it.
The base is the tax shown on your original Form 1040, or on a later return filed by the due date. Because each instalment is tested on its own, a large payment in January does not undo a shortfall in June: the penalty on the earlier instalment runs until the gap is filled.
Relief is narrow. The IRS says the penalty generally cannot be waived for reasonable cause. It may be removed or reduced after a casualty, disaster or other unusual circumstance where imposing it would be unfair, or where you recently retired after reaching the IRS age threshold or became disabled and had reasonable cause. A waiver request is a written explanation signed under penalty of perjury and sent to the address on the notice. Our IRS representation team prepares those responses.
How to pay US estimated tax from the UK
The IRS accepts US tax only in dollars. With a US bank account, the simplest routes are your IRS online account, IRS Direct Pay or EFTPS. From a UK bank with no US routing number, the choices narrow to a card payment through an IRS-approved provider or a same-day wire, with a cheque by post as the slowest option.
Your IRS online account (opens the official IRS page in a new tab) takes estimated payments and shows them by year, which confirms each one reached the right tax year. IRS Direct Pay needs a US bank routing number and does not accept SWIFT codes, and the IRS says neither it nor the online account accepts payments from a foreign bank with no US affiliate. EFTPS is free and suits a schedule set up in advance, but you must enrol first.
For a UK bank, the IRS describes a same-day wire: you complete its same-day taxpayer worksheet with the tax type and period, take it to your bank, and the bank sends dollars through a US correspondent. The IRS warns that banks may charge for this and that it can be costly. A cheque or money order goes with the voucher to the Form 1040-ES address for people living in a foreign country, not the Form 1040 address. If a balance cannot be met in full, the payment plans (opens the official IRS page in a new tab) page sets out the options.
Our tax planning work estimates the year's US position before each instalment, so payments are made only where US tax will remain after the UK credit. The wider filing cycle, from residence to credits, is in our guide for Americans in the UK.
- IRS online account: pay and check estimates by year, US bank needed
- IRS Direct Pay: US routing number required, no SWIFT codes
- EFTPS: no fee, enrolment required, suited to scheduled payments
- Debit or credit card through an approved provider, for a fee
- Same-day wire from a UK bank with a US banking relationship
General information, not advice. The right answer depends on your circumstances and the tax year concerned.
