How the UK Tax System Works for Americans

The UK tax system taxes income in bands from 0% to 45%, runs its tax year from 6 April to 5 April, and collects most tax automatically from your pay through PAYE, with National Insurance charged separately on your earnings. As an American in the UK, you follow these same UK rules, and for most employees, the UK calculates and collects the tax for you. This guide explains how it works, so you know what you are paying and when.

The UK tax system in brief:

• The tax year runs from 6 April to 5 April, not the calendar year.
• Income tax is charged in bands: 0% up to £12,570, then 20%, 40%, and 45%.
• PAYE automatically takes tax from your paycheck, so most employees never file.
• National Insurance is a separate tax that funds the NHS and the State Pension.

Two things this page does not cover: how UK tax compares to U.S. tax (see our guide to UK vs. U.S. taxes) and how to file your U.S. return from the UK (see our guide to U.S. expat taxes in the UK).

UK Tax at a Glance for 2025/26

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Are You a UK Tax Resident?

Whether the UK taxes you at all depends on residency, as determined by the Statutory Residence Test. If you spend 183 or more days in the UK in a tax year, you are a UK tax resident. Below that, a “sufficient ties” test weighs factors like having a home, family, or work in the UK against the number of days you spend there.

UK tax residents are generally taxed on their worldwide income, the same way the U.S. taxes its citizens, which is why Americans living in the UK usually fall under both systems at once, part of the wider picture in our full UK country guide. How you then avoid being taxed twice is a U.S. filing matter, covered in our guide to U.S. expat taxes in the UK.

The UK Tax Year Runs From 6 April to 5 April

The UK tax year is the 12-month period the government uses to assess income tax, and it runs from 6 April to 5 April the following year, not the calendar year. So the 2025/26 tax year runs from 6 April 2025 to 5 April 2026, and every allowance, band, and threshold resets on 6 April.

This matters for two reasons. First, your UK income is measured over a different period than your U.S. income, which runs January to December, so the two never line up cleanly. Second, UK deadlines are tied to this calendar: if you have to file a UK return, it is due by the following 31 January. For most employees, though, the tax year passes without any filing at all, because PAYE settles the bill as you go.

UK Income Tax Bands and Rates

The UK charges income tax in bands, and you only pay each rate on the slice of income that falls inside that band. For England, Wales, and Northern Ireland, the income tax rates for 2025/26 are:

A common mistake is assuming that crossing into a higher band taxes all your income at the higher rate. It does not. If you earn £55,000, only the roughly £4,700 above £50,270 is taxed at 40%; everything below is taxed at 0% and 20%. These thresholds are frozen through to 2028, which means pay rises can quietly pull more of your income into higher bands over time.

The Personal Allowance and the £100,000 Trap

Everyone starts with a Personal Allowance of £12,570 that is taxed at 0%. The catch is that the allowance shrinks once you earn a lot. For every £2 you earn above £100,000, you lose £1 of your allowance, and it disappears entirely at £125,140.

The effect is a hidden 60% marginal rate on income between £100,000 and £125,140, often called the 60% tax trap, because you pay 40% on that income and lose allowance at the same time. It is higher than the 45% additional rate that applies above £125,140, and it is one of the quirks that surprises higher earners most when they arrive in the UK.

Scotland Has Its Own Income Tax Bands

If you live in Scotland, your income tax is set by the Scottish Parliament and uses six bands rather than three. The Scottish rates for 2025/26 are:

Scotland sets rates only on earned and pension income; savings and dividends still follow the rates for the rest of the UK. Where you live on the last day of the tax year generally decides which system applies, so an American in Edinburgh is taxed on the Scottish bands.

National Insurance Is a Separate Tax on Earnings

In addition to income tax, the UK charges National Insurance on earnings. It is separate from income tax, funds the NHS, the State Pension, and certain benefits, and is not affected by your Personal Allowance.

For employees, National Insurance comes out automatically through PAYE alongside income tax. If you are an American on a temporary UK assignment, the U.S.-UK Totalization Agreement determines which country’s system you pay into, so you are not charged social taxes by both countries.

PAYE Collects Tax Automatically From Your Pay

Most employees in the UK never file a tax return, because tax is deducted from each paycheck under Pay As You Earn (PAYE). Your employer calculates the tax and National Insurance due, sends it to HMRC, and pays you the balance. By the end of the year, the right amount of tax has usually been collected without you doing anything.

The system runs on your tax code, a short code on your payslip that tells your employer how much tax-free allowance to apply. If your code is wrong, for example, after starting a new job or having more than one source of income, you can end up paying too much or too little, so it is worth checking your payslip when your circumstances change.

When You Need to File a UK Self-Assessment

Not everyone escapes filing. You generally need to complete a Self Assessment tax return if you are self-employed, earn over £150,000, have significant rental income or investment income, or owe tax that PAYE cannot collect. The online deadline is 31 January, after the tax year ends.

Because most Americans in the UK are also filing a U.S. return, the interaction between the two systems matters, but the UK return itself follows UK rules. Our Self Assessment guide covers who must file and how; if the digital-filing rules apply to you, see our guide to Making Tax Digital.

How the UK Taxes Savings, Dividends, and Gains

Beyond your salary, the UK taxes other income at its own rates and with its own allowances:

• Savings interest: a Personal Savings Allowance lets basic-rate taxpayers earn £1,000 of interest tax-free, and higher-rate taxpayers £500, before any tax applies.
• Dividends: the first £500 of dividends is tax-free; thereafter, dividends are taxed at 8.75%, 33.75%, or 39.35% depending on your tax band.
• Capital gains: gains above a £3,000 annual exemption are taxed at 18% or 24%. Property gains have their own rules, covered in our guide to UK capital gains tax on property.

One thing to keep in mind as an American: some accounts the UK treats as tax-free, such as an ISA, are not tax-free on your U.S. return, but that is a U.S. filing question rather than a UK one.

A Real-World Example: James’s UK Tax on a £55,000 Salary

James is an American working in Manchester on a £55,000 salary in 2025/26, with no other income.

• Personal Allowance: the first £12,570 is taxed at 0%.
• Basic rate: the £37,700 between £12,571 and £50,270 is taxed at 20%, which is £7,540.
• Higher rate: the £4,730 between £50,271 and £55,000 is taxed at 40%, which is £1,892.
• National Insurance: roughly £3,110 for the year at 8% and 2%.

His total income tax is about £9,432, and National Insurance is about £3,110, all collected automatically through PAYE, so James takes home around £42,500 and never files a UK return. His U.S. return is separate, and the UK tax he paid here is what he uses to offset it.

How Greenback Can Help

The UK system is manageable once you can see how the pieces fit, but it rarely stands alone for an American, because your UK tax feeds directly into your U.S. return. We prepare both sides together, so the figures line up and nothing falls through the gap between the two systems.

If you would like both your UK and U.S. taxes handled by one team, our UK tax services pair a UK Chartered Accountant with a U.S. accountant on a single account. Learn more about how we help Americans living in the UK.

One team, one account for UK and U.S. taxes.

Get your UK and U.S. taxes handled together. Greenback helps Americans in the UK file with confidence.

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Frequently Asked Questions

This article is for general informational purposes only and does not constitute tax advice. UK tax rules, rates, and thresholds change, and individual circumstances vary. Check current figures on official UK government sources and consult a qualified tax professional about your situation.