Moving from the US to the UK: Your First-Year Tax Roadmap

Moving from the US to the UK: Your First-Year Tax Roadmap

You're leaving the United States for a fresh start in the UK. Exciting—but your tax obligations don't simply follow you across the Atlantic. American citizens and long-term residents face a complex first year: you'll likely owe taxes to both countries, navigate unfamiliar UK reporting rules, and potentially miss out on legitimate deductions if you don't plan carefully. This guide walks you through the essential steps, thresholds, and timelines so you can avoid costly mistakes and position yourself for tax efficiency from day one.

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Your US Tax Status Doesn't Stop at Departure

Here's the critical fact: the United States taxes citizens on worldwide income regardless of where they live. If you hold US citizenship or a green card, the IRS considers you a US tax resident for filing purposes—even if you've just relocated to London, Edinburgh, or Manchester.

This means in your first year, you will typically file:

• A US federal tax return (Form 1040) reporting global income earned through 31 December
• A UK Self-Assessment Tax Return (if applicable), reporting income earned in the UK and, potentially, worldwide income
• Additional US forms such as FATCA Form 8938 (if you hold foreign financial assets exceeding certain thresholds) or FinCEN Form 114 (FBAR) if you maintain foreign bank accounts

Understanding this dual obligation early prevents panic in January and ensures you meet both countries' deadlines.

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Determining Your UK Tax Residency Status

Your first critical task is establishing your Statutory Residence Test (SRT) status for the tax year in which you move. This test, administered by HMRC, determines whether you are regarded as a UK resident for tax purposes and therefore liable to UK tax on worldwide income.

Under the SRT, you will typically be considered UK resident if:

• You spend 183 or more days in the UK during the tax year (6 April – 5 April)
• You work full-time in the UK for an entire tax year
• You have a UK home available for at least 91 days and spend at least 16 days there

Conversely, you may be non-resident if you:

• Spend fewer than 16 days in the UK and do not work in the UK
• Spend fewer than 91 days in the UK and have not been UK resident in the previous three years

Your residency status affects which income is taxed in the UK. If you arrive on 1 June, you'll be non-resident for part of the tax year (6 April – 31 May) and resident from 1 June onwards. Income you earned in the US before arrival may not be subject to UK tax; income earned after your residency date typically is.

It's essential to notify HMRC of your arrival and confirm your status. A licensed UK tax adviser can help you file the correct form and avoid triggering unnecessary tax liabilities.

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Foreign Earned Income Exclusion and Tax Treaty Relief

The US-UK tax treaty and the Foreign Earned Income Exclusion (FEIE) are your first defense against double taxation.

Foreign Earned Income Exclusion (FEIE)

If you qualify, you may exclude up to a threshold amount of foreign earned income (wages, self-employment income) from US federal taxation for the first year. The threshold is adjusted annually; consult the IRS FEIE guidance for the current year's figure. This exclusion applies only to income you earned while physically outside the US and only to earned income—not investment income, pensions, or rental revenue.

US-UK Tax Treaty

The US-UK Income and Gains Tax Treaty provides additional relief. For example:

• Pension income may be taxed only in the country of residence
• Rental income from UK property is taxed in the UK; the US allows a foreign tax credit
• Dividends and interest are subject to reduced withholding rates

Proper treaty planning ensures you claim all available exemptions and credits, minimizing your effective global tax rate.

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The Foreign Tax Credit (FTC) and Reconciling Dual Liabilities

Once you've calculated your US and UK tax, you face the reality: both countries may tax the same income. The Foreign Tax Credit (FTC) allows you to offset UK taxes paid against your US federal liability, dollar-for-dollar (up to your US tax on foreign income).

How it works:

1. Calculate US tax on worldwide income (minus FEIE or other exclusions)

2. Calculate UK tax on UK-resident income

3. Claim the FTC on your US return (Form 1040, Schedule 3 or Form 1118 if complex) for UK taxes actually paid

4. Pay the difference to whichever country results in a net liability

Example scenario: You earn £40,000 in UK wages. The UK tax is £4,500. Your US tax on the same income (after FEIE) is $5,600. You claim a $4,500 credit, reducing your US liability to $1,100 net.

If UK taxes exceed US taxes on the same income, you may carry unused credits forward (subject to limitations). This is where precise reporting matters—errors cost money.

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First-Year Timing and Deadlines

Your US and UK tax years do not align, which complicates first-year filing:

| Deadline | Filing | Jurisdiction |

|---|---|---|

| 15 April (US) or 4 months after departure | Form 1040, including FEIE, FTC | IRS |

| 31 January (following tax year) | Self-Assessment Tax Return | HMRC |

| 15 October (with extension) | FBAR (FinCEN Form 114) | FinCEN |

You may qualify for an automatic extension on your US return if you are a qualifying expat. File Form 2350 before the April deadline to extend to June 15.

For your first year specifically: if you depart the US mid-year, you still file a full-year Form 1040. Your UK tax year runs 6 April – 5 April, so your first UK Self-Assessment covers the period from arrival to the following 5 April.

Missing a deadline can result in penalties, interest, and even loss of treaty benefits. Engaging a licensed professional ensures you file on time and claim all available relief.

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Structuring Deductions and Credits for Maximum Benefit

Your first-year deductions and credits require careful coordination:

US-Side Deductions

• FEIE (up to the threshold): available if you meet the physical presence test or bona fide residence test
• Foreign Tax Credit: claim on Schedule 3 or Form 1118
• Charitable donations: if you itemize, only donations to US and qualifying UK charities count
• Student loan interest, IRA contributions: these reduce US taxable income before applying FEIE

UK-Side Allowances

• Personal Allowance: up to the threshold (adjusted annually) if you are a UK resident
• Marriage Allowance: if applicable and you marry a UK resident
• Trading allowance: if self-employed (up to £1,000, claim-free)
• Residence nil-rate band: relevant if you own UK property

Many expats leave money on the table by not coordinating these across jurisdictions. A global tax calculator can help you model scenarios and confirm the optimal filing strategy before you file.

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National Insurance and Payroll Obligations

If you're employed in the UK, your employer will enroll you in the National Insurance (NI) system and operate Pay As You Earn (PAYE). National Insurance contributions are separate from income tax but are withheld at source. The rate depends on your employment status, age, and salary level.

For US citizens, this creates a unique complication: you may owe US self-employment tax on UK employment income in addition to UK National Insurance. The US-UK treaty offers limited relief; you cannot simply offset NI against US self-employment tax. Ensure your US return correctly reports UK employment income and any NI paid for potential future treaty amendments or legislative relief.

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Common First-Year Pitfalls to Avoid

1. Filing only to one country. Both the US and UK expect you to file; silence invites audits and penalties.

2. Claiming FEIE without documenting the physical presence test. Keep records of all travel dates.

3. Forgetting FBAR and FATCA filings. These carry severe penalties (up to 50% of account value for FBAR) and are separate from income tax.

4. Not notifying HMRC of arrival. Delayed notification can cause a tax assessment to be raised at the wrong address.

5. Overpaying tax by not using the FTC. Many expats file but forget to claim credits, handing money to the government.

6. Underestimating self-employment income. If you freelance or consult, both countries want accurate reporting.

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Planning Beyond Year One

Your first year sets the stage. Once you've settled, consider:

• Pension planning: UK pensions (SIPPs, pensions from UK employers) are treated differently by the US, and vice versa. Maximize contributions early.
• Property ownership: buying a UK home triggers different tax treatment in each jurisdiction; plan before purchase.
• Spousal filing: if you marry a UK resident, explore filing strategies and treaty benefits.
• Permanent establishment: if self-employed, ensure you do not accidentally create a taxable presence in the US.

A global tax calculator updated annually helps you track these changes and adjust your strategy.

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What to Gather Before You File

Organize the following documents for your professional adviser:

• US employment income: W-2s, 1099s, offer letters
• UK employment or self-employment income: payslips, Unique Taxpayer References, accountancy records
• Foreign financial accounts: bank statements, investment accounts, pension statements (names and balances)
• Travel records: passport stamps, flights, hotel receipts (to document FEIE physical presence or UK residency days)
• Property records: rental income, mortgage interest, council tax, maintenance costs
• Donations and charitable gifts: receipts and donor records
• Taxes paid: documentation of UK tax paid (P60, Self-Assessment Statement of Account)

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The Bottom Line

Moving from the US to the UK is entirely manageable from a tax perspective—but only with accurate, timely planning. You have dual filing obligations, overlapping deadlines, and significant credits and exclusions available if you claim them correctly. Missing even one form (like FBAR) or miscalculating one credit can cost thousands in penalties or lost relief.

This is where a licensed professional—a CPA with expat experience in the US and a chartered accountant registered with the UK tax authority—becomes essential. A trusted adviser reviews your situation holistically, ensures you meet both countries' requirements, and identifies deductions and credits specific to your circumstances.

Your first year sets expectations and creates a tax record. Invest in getting it right.

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Next Steps

If you're planning a move or have just arrived in the UK, start by calculating your tax exposure. Use our global tax calculator to model your US and UK liability side-by-side, see where you'll owe tax, and identify major deductions or credits you may claim.

Then, book a consultation with one of our licensed professionals. We'll confirm your residency status, review your income streams, coordinate your filings, and ensure you comply with both the IRS and HMRC while minimizing your overall tax burden.

Your move should be exciting, not stressful. Let us handle the tax complexity.

Frequently asked questions

Do I have to file a US tax return if I'm now a UK resident?

Yes. US citizens and green card holders must file a US federal return annually, regardless of residency. You'll report worldwide income and can claim the Foreign Earned Income Exclusion or Foreign Tax Credit to reduce double taxation.

When do I become a UK tax resident?

Your UK residency status is determined by the Statutory Residence Test (SRT), which typically looks at how many days you spend in the UK, whether you work full-time there, and whether you have a home available. Consult HMRC's guidance or a UK tax adviser for your specific date.

Can I exclude all my UK income from US tax in my first year?

You can exclude earned income (wages, self-employment) up to the annual Foreign Earned Income Exclusion threshold *if* you meet the physical presence or bona fide residence test. Investment income, pensions, and rental income do not qualify for the exclusion.

What if I owe tax to both countries?

Use the Foreign Tax Credit on your US return to offset UK taxes paid. If UK tax exceeds US tax on the same income, you may carry the excess forward; if US tax is higher, you pay the difference to the IRS.

Do I need to file FBAR and FATCA forms?

If you hold foreign financial accounts totaling over $10,000 at any point in the year, you must file FBAR (Form 114). If you hold specified foreign financial assets over a threshold, FATCA (Form 8938) is also required. Both carry steep penalties for non-filing.