Last updated: 14 October 2026
What do you gain by filing your monthly CIS return online?
Filing online is now the only practical way to send a monthly Construction Industry Scheme (CIS) return. HMRC’s online service and commercial CIS software check figures as you go, give you an instant receipt, and let you verify subcontractors at the same time. Returns are due by the 19th of each month, covering payments made from the 6th of the previous month to the 5th of the current one. Late returns bring automatic penalties, even if you made no payments.
Benefits of filing online
- Instant confirmation that HMRC has received the return
- Built-in checks reduce errors in subcontractor details
- You can verify new subcontractors online and get their deduction rate immediately
- Nil returns can be filed quickly when no payments were made
- Payment and deduction statements can be produced from the same software
Deadlines and penalties
| Lateness | Penalty |
| 1 day late | £100 |
| 2 months late | Further £200 |
| 6 months late | £300 or 5% of the CIS deductions, whichever is higher |
| 12 months late | Further £300 or 5%, or up to 100% if deliberate |
What goes on the return
- Each subcontractor’s name and UTR or verification number
- Gross payment, cost of materials and amount deducted
- A declaration about employment status
- A declaration that subcontractors have been verified
Example
Davies Building Ltd pays four subcontractors in the month to 5 November 2026. It files its return online using its payroll software on 15 November. The software checks each subcontractor’s UTR and shows the deductions: £1,200 at 20% for three verified subcontractors and £300 at 30% for one who isn’t registered. The CIS deductions are paid to HMRC by 22 November, with the PAYE.
Nil returns
If you didn’t pay any subcontractors in a month, you must still file a nil return, or tell HMRC that you’re inactive for up to 6 months. Forgetting a nil return is one of the most common causes of CIS penalties.
Changes from April 2026
Following measures announced in the Budget, HMRC is tightening the rules on gross payment status and making it easier to remove it from businesses involved in fraud. Contractors should keep records showing they checked their supply chain.
Subcontractors
Subcontractors receive payment and deduction statements each month. Sole traders claim the deductions on their Self Assessment returns. Limited companies set them against their PAYE liabilities through the EPS.
Common mistakes
- Forgetting to file a nil return in a quiet month
- Deducting CIS from the cost of materials, which should be excluded
- Paying a subcontractor before verifying them
- Treating a worker as a subcontractor when they are really an employee
- Not giving subcontractors their monthly statements within 14 days of the end of the tax month
If you only take on subcontractors occasionally, set a monthly reminder for the 19th so a return is never missed.
Frequently asked questions
Can I file a paper CIS return?
HMRC strongly encourages online filing; paper filing is very limited.
How do I appeal a penalty?
Within 30 days, if you have a reasonable excuse.
Do I need special software?
HMRC’s online service works for small contractors.
What if I made a mistake?
You can amend the return online.
Related: registering a subcontractor for gross payment status, CIS registration for a carpet fitter and scanned signatures on form 64-8.
Talk to Accotax
Want this handled for you? Our team at Accotax can help with CIS returns and compliance. See our CIS accountants service, or contact us for a free, no-obligation quote.
This page is general guidance based on HMRC rules for the 2026/27 tax year, checked against gov.uk on 14 October 2026. It is not personal advice, so speak to an accountant about your own situation.
