US vs UK Tax System Explained: Key Differences for Workers

If you have worked in both the US and the UK—or are considering a move between them—the tax systems can feel like different planets. Both use progressive income tax, but the structures, terminology, and social contributions are different enough that comparing a US salary to a UK salary is not straightforward. This guide lays out the key differences so you can make sense of the numbers.

The basics: how each system works

- US: Federal income tax (7 brackets, 10 %–37 %) + state income tax (0 %–13.3 % depending on state) + FICA (Social Security at 6.2 % + Medicare at 1.45 %). You file annually with the IRS; withholding from each paycheck is based on your W-4 form. - UK: Income tax (3–4 bands, 0 %–45 % in England/Wales/NI; Scotland has its own bands) + National Insurance (NI, with different rates at different earnings thresholds). Tax is deducted automatically through PAYE (Pay As You Earn); most people never file a return.

The biggest structural difference: the US has a federal-plus-state system, so your tax depends heavily on where you live. A $100,000 salary in Texas is taxed very differently from $100,000 in California. The UK has a national system (with Scotland as a partial exception), so your take-home is the same whether you live in London or Leeds.

Income tax brackets compared

US federal brackets (2025/26, single filer): 10 %, 12 %, 22 %, 24 %, 32 %, 35 %, 37 %. UK bands (2025/26, England): 0 % (personal allowance up to £12,570), 20 % (basic rate up to £50,270), 40 % (higher rate up to £125,140), 45 % (additional rate above £125,140).

At a $70,000 / £55,000 salary (roughly equivalent at typical exchange rates), the effective income tax rate is fairly similar—but the composition is different. The UK has a more generous personal allowance (£12,570 vs. a standard deduction of ~$14,600 in the US), but the jump to 40 % at £50,270 is sharp. In the US, the 22 % bracket covers a wide range ($47k–$100k), so you stay at a lower marginal rate longer. Run both through our Net Salary Calculator to compare—for example, $70,000 in California vs £55,000 in the UK.

Social contributions: FICA vs National Insurance

In the US, FICA (Social Security + Medicare) takes 7.65 % of your gross pay. In the UK, National Insurance takes a variable rate—currently 8 % on earnings between the primary threshold (~£12,570) and the upper earnings limit (~£50,270), then 2 % above that. At mid-range salaries, the NI burden is roughly similar to FICA.

The key difference is what you get in return. In the UK, National Insurance funds the NHS (healthcare) and the State Pension. In the US, FICA funds Social Security and Medicare—but most working-age Americans also need employer-provided or individually purchased health insurance, which is an additional cost that does not show up in the tax comparison.

Healthcare: the hidden cost

This is the single biggest factor that tax comparisons usually miss. In the UK, healthcare is free at the point of use through the NHS. In the US, health insurance is often a major expense—either deducted from your paycheck (pre-tax, typically $100–$500+ per month for employee-only coverage in an employer plan) or purchased individually (potentially much more). When comparing a US salary to a UK salary, you should account for the healthcare cost in the US that the UK worker does not face.

How to compare a US offer vs a UK offer

Step 1: Convert both to net using our Net Salary Calculator. Step 2: For the US offer, subtract your expected healthcare premium if it is not free. Step 3: Adjust for cost of living using our Cost of Living Calculator—e.g., New York vs London. Step 4: Or use Job Offer Compare to do steps 1 and 3 in one go.

The result will tell you which offer gives you more real purchasing power. Our guide on How to compare job offers walks through this in more detail.

Other differences worth knowing

- Filing: Most UK workers never file a return (PAYE handles it automatically). US workers must file annually by April 15. - Capital gains: Both countries tax capital gains, but rates and allowances differ significantly. - Pensions/retirement: The US has 401(k) with employer match; the UK has auto-enrolment workplace pensions. Both reduce taxable income. - Tax year: US is January–December. UK is April 6–April 5.

All figures here are estimates. Tax law changes frequently in both countries—check with the IRS and HMRC for the latest, or consult a cross-border tax specialist if you are making a move.