What does a CIS accountant do? They check the tax your contractors deduct under the Construction Industry Scheme, file your Self Assessment return and claim back anything you have overpaid.
Most subcontractors have 20% taken from every invoice, so a good CIS accountant usually pays for themselves through a larger rebate.
If you are a builder, plumber, electrician or other tradesperson, HMRC uses CIS to collect tax before the money reaches you. That often means overpaying during the year and waiting until your self assessment tax return is filed to get the difference back.
At R&R Chartered Certified Accountants we help subcontractors across Blackburn, Lancashire and the North West stay on top of CIS deductions and claim rebates. Below is a plain-English guide to what a CIS accountant does, what affects the cost and how to choose one.
Want it handled for you? If you would rather hand the whole thing over, our CIS accountant service handles monthly returns, deduction statements and rebate claims for subcontractors, and we work with trades of every size as accountants for construction and engineering businesses.
What Does a CIS Accountant Do?
A CIS accountant is an accountant who understands the Construction Industry Scheme and the tax issues subcontractors face. Their job is to make sure you pay the right tax, claim back what you are owed, and keep records that satisfy HMRC.
The main tasks include:
- Checking your CIS statements and the deductions your contractor has made.
- Preparing and filing your self assessment tax return after the tax year ends.
- Claiming a CIS tax rebate if too much tax was deducted.
- Advising on allowable expenses such as tools, vehicle costs, protective clothing and home office use.
- Helping you apply for gross payment status, so contractors pay you without deducting tax.
- Keeping your bookkeeping organised, often in cloud software like Xero or QuickBooks.
How much does a CIS accountant cost?
Fees depend on how much support you need. A year-end Self Assessment return on its own is the simplest job. Monthly bookkeeping, VAT returns and ongoing advice add to the work.
We agree a fixed fee after a short discovery call, so you know the cost before anything starts.
Compare like for like. A cheap service that only files your return may miss expenses or errors in your CIS statements. A fee that includes a proper review often pays for itself through a larger rebate or a lower tax bill.
How do you choose a CIS accountant?
Not every accountant knows CIS well. Look for:
- CIS experience: they work with subcontractors regularly and understand CIS statements, gross payment status and rebate claims.
- Fixed or transparent fees: you know the price before work starts, with no surprise add-ons.
- Cloud accounting knowledge: most now use Xero, QuickBooks or FreeAgent, so you can see your figures in real time.
- Local availability: much is done online, but an accountant who knows your area and local trades helps.
- Clear communication: someone who explains things plainly and replies promptly, especially near HMRC deadlines.
When should you hire a CIS accountant?
As soon as you start working under CIS, or as soon as you see deductions taken from your pay. The earlier you get organised, the easier it is to claim everything and avoid a rush before the 31 January deadline.
If you are owed a CIS rebate now, an accountant can claim it for you rather than leaving it unclaimed.
HMRC’s guidance is in the Construction Industry Scheme overview on GOV.UK. You can check contractors’ company details at Companies House.
Frequently Asked Questions
A CIS accountant is an accountant who specialises in the Construction Industry Scheme. They help subcontractors file tax returns, claim CIS rebates, apply for gross payment status and manage construction-related expenses.
You do not legally need one, but many subcontractors benefit from professional help. CIS tax rules can be confusing, and an accountant usually increases your rebate and reduces the risk of HMRC penalties.
Contractors normally deduct 20% if you are registered with HMRC under CIS, or 30% if you are not registered. These deductions count as advance payments towards your income tax and National Insurance.
Yes. A CIS accountant can review your tax compliance history, turnover and other HMRC requirements, then help you apply for gross payment status so contractors pay you without deducting tax.
Keep all CIS payment and deduction statements, invoices, receipts for materials and expenses, bank statements and mileage logs. Good records make your tax return accurate and maximise your rebate.
The bottom line
A good CIS accountant does more than file your return. They check your deductions are right, claim your expenses properly and make your rebate as large as it should be.
If you need a CIS accountant, see what our CIS accountant service covers or get in touch with R&R Chartered Certified Accountants for a free consultation.
Tax figures checked by Rehan Razzaq FCCA on 8 October 2026 for the 2026/27 tax year.
This article is general guidance for UK businesses and individuals and does not constitute personal financial or tax advice. Rules, thresholds and individual circumstances vary — always confirm your specific position with a qualified accountant before acting.
Rehan Razzaq, FCCA
Founder, R&R Chartered Certified Accountants
ACCA Chartered Certified and Xero Certified Advisor, helping UK small businesses and subcontractors with accounts, tax and financial planning since 2021.
We work with clients right across Lancashire and the North West. If you are looking for accountants in Blackburn, or a local accountant in Nelson or accountant in Accrington, our team is a short drive away.
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