Builders and trades: how CIS deductions land on an American tax return

Figures relate to tax year 2025-26 (UK) · 2025 (US)

You work as a subcontractor on British sites, and every payment arrives short. The contractor takes CIS deductions at 20% and sends them to HMRC. For an American tradesperson, that withholding changes how you build the American return.

The mistake we see most often is reporting the net figure. So this guide covers what the scheme does, which number belongs on your US return, how the credit works, and where self-employment tax fits.

Key takeaways

• CIS deductions are advance payments toward your British tax, not a final tax.
• Your US return reports gross income before the deduction, not the amount you received.
• The British tax finally due, after your Self Assessment, is what supports the foreign tax credit.
• Materials you supply come out before the deduction is calculated.
• Self-employment tax can apply unless a certificate of coverage shifts you to British National Insurance.
• Repayments from HMRC change the credit, so the timing matters.

What is the Construction Industry Scheme?

According to HMRC guidance, it is the British system that makes contractors withhold tax from payments to subcontractors in construction. The standard rate is 20% for registered subcontractors and 30% for those who are not. Some qualify for gross payment status and receive the full amount.

The deduction covers income tax and National Insurance on account. Contractors calculate it on the labor element of the payment, not on materials you supplied.

Who has to register?

Anyone working as a subcontractor in construction, and any business paying subcontractors. Registration is free and takes minutes. Without it, contractors must deduct at 30% rather than 20%, so the cost of skipping it shows up in the very first payment.

Registration matters for your American return too. A higher rate means more tax withheld in the year, and a bigger repayment later, which makes the credit harder to line up.

What counts as construction work?

More than people expect. Site preparation, alterations, repairs, decorating and demolition all count, alongside building work itself. Some trades fall outside, including architecture, surveying and carpet fitting. Those definitions decide whether CIS deductions apply to a job at all.

Mixed contracts follow the main purpose of the work. A single invoice covering scheme work and other services needs care, because the contractor decides what to deduct from.

Which figure goes on the American return?

The gross amount, before the deduction. Your business income is what the contractor agreed to pay, not what arrived in your account. The withheld amount is tax paid on your behalf, so it belongs in the tax column rather than netted off income.

Reporting the net figure understates income and overstates nothing. It also loses you the credit for tax already suffered, which usually costs more than it saves.

How the credit actually works

Per IRS rules on the foreign tax credit, the credit follows your final British liability rather than the amount withheld. CIS deductions are payments on account, so your Self Assessment settles the real figure months later. If HMRC repays part of it, the credit on your American return reduces to match.

That timing gap causes most of the trouble. The deduction happens during the British tax year, the refund arrives after it, and the American return sits on a calendar year in between.

Our guide to exchange rates on a US return covers how to convert both the income and the tax consistently.

Why do so many subcontractors overpay?

Because 20% of gross labor is usually more than the tax actually due. Once expenses, the personal allowance and business costs come off, most subcontractors have paid too much. A repayment follows the Self Assessment return, sometimes several thousand pounds.

That repayment is not free money. It reduces the British tax you finally paid, which reduces the credit available on your American return for the same period.

Self-employment tax on construction income

American self-employment tax applies to your profit at 15.3%, and the exclusion does not touch it. For a subcontractor living in Britain and paying National Insurance, a certificate of coverage can remove the American charge instead.

For most subcontractors this saving beats every other adjustment. Our guide to the certificate of coverage explains how to obtain one and how to reclaim earlier years.

Verification and the 30% rate

Contractors verify each subcontractor with HMRC before the first payment. The answer sets the rate: gross, 20% or 30%. A new subcontractor who has not registered gets the higher rate until the records catch up.

So register before your first invoice, not after. Fixing the rate later means waiting for a repayment rather than keeping the cash.

How do CIS deductions affect cash flow?

They take a fifth of your labor income before you see it. On a £4,000 monthly invoice that is £800 gone, every month, until Self Assessment settles up. Many subcontractors plan around that gap without knowing a refund is coming.

The American return does not change the cash position, but it can add to it. Self-employment tax of 15.3% on the same profit lands on top unless coverage removes it.

A worked example

The figures below are illustrative. Take an example: an American carpenter in Bristol invoices £62,000 for labor and £9,000 for materials during the British tax year.

The contractors deduct 20% of the labor element, so £12,400 goes to HMRC. The carpenter receives £58,600, and the American return still reports £71,000 of gross income.

After van costs, tools and the personal allowance, the true British bill comes to about £9,800. HMRC repays roughly £2,600, so the credit on the American return reflects £9,800 rather than the £12,400 withheld.

The American return also shows self-employment tax of roughly $10,000 on that profit, unless a certificate of coverage removes it. For this carpenter, obtaining one is worth more than every other adjustment combined.

Gross payment status

Subcontractors who meet turnover, compliance and business tests can apply for gross payment. No deduction comes off, and Self Assessment settles the whole liability instead. It helps cash flow considerably.

For an American filer it also simplifies the return. There is no withheld figure to track, and the credit follows the tax actually paid on the Self Assessment.

The compliance test is strict. Late returns or late payments can cost the status, and getting it back takes time.

Does the scheme apply to a limited company?

Yes, and the mechanics change. A company registers as a subcontractor, suffers CIS deductions on its invoices, and sets them against its payroll liabilities each month. Any excess is repaid after the payroll year ends.

For an American owner, the company adds a layer. The profit belongs to the company first, and your own return reports salary and dividends rather than trading profit.

That choice deserves a proper comparison. A company can save British tax while creating American reporting that costs more than the saving.

What records should you keep?

Every payment and deduction statement from every contractor, plus your own invoices. Contractors must give you a statement for each payment period showing the gross amount, the materials and the deduction. Those statements are the backbone of both returns.

1. Collect a deduction statement from each contractor for every payment period.
2. Keep invoices showing the split between labor and materials.
3. Record gross income by date, not by the amount that reached your bank.
4. Total the deductions for the British tax year and reconcile them to the statements.
5. Prepare the Self Assessment to find the real British liability.
6. Convert gross income and final tax into dollars on a consistent basis.
7. Report gross income on the American return and claim credit for the final British tax.

What if you also employ people?

Then you may be a contractor as well as a subcontractor. You register in both capacities, deduct from payments to your own subcontractors, and file monthly returns with HMRC. The American side sees a larger business with payroll costs to match.

Running payroll adds British obligations that have no American equivalent. The profit figure still flows to Schedule C, but the supporting records grow considerably.

Do CIS deductions cover National Insurance?

Partly. The deduction counts toward your income tax and Class 4 National Insurance for the year. Class 2 contributions, where you choose to pay them, sit outside it. So the deduction is not a complete answer to your British liability.

That matters when you check your contribution record. Tax paid through the scheme does not automatically build a State Pension record, and gaps can appear without anyone noticing.

When does the repayment arrive?

After you file the Self Assessment for the tax year, usually within a few weeks. Filing in April rather than January brings the money forward by months. Many subcontractors wait, then wonder where the cash went.

For an American filer the timing has a second effect. A repayment received in one calendar year adjusts the credit for the British year it belongs to, so keep both dates on record.

What if you work in both countries?

Then the split matters. Work performed in Britain sits inside the scheme, while work performed in America does not. Your American return reports worldwide profit either way, with credit for the British tax on the British part.

Keep the two streams separate in your books from the start. Splitting them afterwards from bank records is slow and rarely convincing.

Mistakes and penalties we see with CIS deductions

• Reporting net receipts on the American return instead of gross income.
• Claiming credit for the amount withheld rather than the tax finally due.
• Forgetting that an HMRC repayment reduces the credit for that year.
• Paying American self-employment tax without checking social security coverage.
• Losing deduction statements, which makes both returns hard to support.
• Missing the monthly contractor returns when you start employing subcontractors.
• Waiting until January to file, then losing months of use of a refund you were always owed.

HMRC penalties for late monthly returns start quickly and mount. On the American side, understating gross income invites an accuracy penalty, with interest running from the original due date.

None of this is hard once the routine exists. Keep the statements, file on time, and the two returns fall into place each year.

How US UK Tax Accountants helps

We prepare the Self Assessment and the American return together, so the credit reflects the tax you actually paid. Where earlier years reported net figures, we correct them. If you work in construction and file in both countries, get in touch with your deduction statements and we will handle it alongside your US federal returns.

Last reviewed 23 September 2026. This article is general information and not personal tax advice. Rates and registration rules change, so check the current position for your own year.