CIS Return Deadline: A Complete Guide for Contractors and Subcontractors

Written by: Cloudco Books

The Construction Industry Scheme (CIS) plays a crucial role in ensuring that tax is collected fairly within the UK’s construction sector. Whether you’re a contractor paying subcontractors or a subcontractor working on projects, understanding the CIS return deadlines is essential to staying compliant, avoiding penalties, and maintaining good business practices.

This guide will walk you through the CIS monthly return process, explain the deadlines, highlight the consequences of missing CIS returns, and show you how to make payments to HMRC correctly.

Understanding CIS

The Construction Industry Scheme is designed to reduce tax evasion in the construction industry by requiring contractors to deduct tax from subcontractor payments and send it to HMRC. These CIS deductions count as advance payments towards the subcontractor’s income tax and National Insurance.

If you work in the UK construction sector and pay subcontractors, you must register for CIS with HMRC. The scheme applies to most construction work, including building, repairs, demolition, and site preparation. Many people assume that CIS and VAT returns are the same, but in reality, they are very different in several important ways.

Difference Between CIS And VAT Return

AspectCIS ReturnVAT Return
PurposeReports payments to subcontractors and tax deductions under the Construction Industry Scheme.Reports VAT charged on sales and VAT paid on purchases to HMRC.
Who Needs to FileContractors in the UK construction industry who pay subcontractors.Businesses registered for VAT, regardless of industry.
Filing FrequencyMonthly (by the 19th of the following month).Usually quarterly, but can be monthly or annually depending on the VAT scheme.
Information RequiredSubcontractor details, payment amounts, CIS deductions, verification numbers.Sales and purchase records, VAT charged, VAT paid, adjustments.
Payment to HMRCTax deducted from subcontractor payments (CIS tax) is sent to HMRC.VAT owed to HMRC after deducting input VAT from output VAT.
Relevant Law/RulesGoverned by the Construction Industry Scheme rules.Governed by VAT Act and HMRC VAT regulations.
Registration RequirementMust register for CIS with HMRC if paying subcontractors.Must register for VAT if turnover exceeds £90,000 (2025 threshold) or voluntarily.
Common PenaltiesLate filing, incorrect deductions, failing to verify subcontractors.Late submission, late payment, inaccurate VAT records.

Want a deeper insight into VAT returns? Explore our blog on What Is a VAT Return? for everything you need to know.

 What Is a CIS Monthly Return?

A CIS monthly return is a report that contractors must submit to HMRC each month, detailing:

  • Payments to subcontractors
  • CIS deductions made
  • Subcontractors with gross payment status (0% deduction)

Even if no subcontractors were paid in a given month, you still need to file a monthly CIS return stating that no payments were made.

CIS Return Deadlines

The CIS filing deadline is the 19th of each month, covering the previous tax month. A tax month runs from the 6th of one month to the 5th of the next.

Example:
If your tax month runs from 6th April to 5th May, your return must reach HMRC by 19th May.

Key CIS Return Deadlines:

  • 19th: Last date to file the monthly CIS return to HMRC.
  • 22nd: Last date to make electronic payments to HMRC for CIS deductions.

Payment Deadline for CIS Deductions

The payment deadline depends on your method:

  • Electronic payments: by the 22nd of the month.
  • Postal payments: by the 19th of the month.

Filing a CIS Return: How to Do It?

You can file a CIS monthly return using:

  1. HMRC’s online service
  2. Commercial CIS software approved by HMRC

When filing a CIS return, you’ll need:

  • Contractor and subcontractor details
  • Total payments and deductions for the tax month
  • Verification status of subcontractors

Penalties for Missing CIS Return Deadlines

Missing CIS return deadlines can be costly:

Late PeriodPenalty
1 day late£100
2 months lateAdditional £200
6 months lateAdditional £300 or 5% of CIS deductions
12 months lateAdditional £300 or up to 100% of CIS deductions

Penalties apply even if you had no payments to subcontractors, unless you inform HMRC in advance.

Avoiding Penalties: Best Practices

  • Submit early: Don’t wait until the deadline.
  • Use reminders: Set up alerts for the 19th and 22nd.
  • Keep CIS records: Maintain payment and deduction logs for all subcontractors.
  • Verify subcontractors: Ensure correct deduction rates (20%, 30%, or 0%).

Claiming Your CIS Refund

If you’ve paid too much tax through CIS deductions, you can claim your CIS refund:

  • Self-employed subcontractors: via self-assessment tax returns.
  • Limited companies: by offsetting against CIS tax liabilities or corporation tax.

CIS Statements for Subcontractors

If you’ve made deductions from a subcontractor’s pay, you must issue a CIS statement. This document shows:

  • Payment amount
  • Deduction amount
  • Verification reference

Why the CIS Deadline Matters?

Meeting the CIS return deadlines keeps you compliant with CIS rules, helps avoid unnecessary penalties for late filing, and ensures your payments to HMRC are accurate. Missing deadlines can trigger financial penalties, damage relationships with subcontractors, and even cause compliance investigations.

Why Choose CloudCo Books for Your CIS Return?

Filing a CIS monthly return correctly and on time is crucial to staying compliant with HMRC and avoiding costly penalties. At CloudCo Books, we specialise in making the Construction Industry Scheme process smooth, accurate, and stress-free for contractors.

Here’s why businesses choose us for their CIS returns:

BenefitHow CloudCo Helps
Accuracy GuaranteedWe ensure your subcontractor details, deductions, and payments are recorded and submitted correctly.
On-Time FilingOur automated reminders and proactive approach mean you’ll never miss the CIS return deadline.
Expert SupportOur CIS return assistants understand HMRC’s requirements and can guide you through every step.
Complete ComplianceWe handle subcontractor verification, maintain CIS records, and submit your returns through HMRC’s approved systems.
Time-SavingWe take the admin burden off your hands so you can focus on running your business.
Refund AssistanceWe help you claim your CIS tax refund quickly and efficiently when you’ve overpaid.

With CloudCo Books, you get a reliable partner who ensures your CIS returns are always filed with HMRC accurately, on time, and without stress.

Final Thoughts

The CIS deadline is a critical part of the UK construction industry scheme. Contractors must file monthly CIS returns, make CIS payments on time, and keep accurate records of payments to subcontractors and deductions.

By understanding the CIS return deadlines and taking steps to file on time, you can avoid penalties, keep your business running smoothly, and maintain good standing with HMRC.

Whether you file directly via HMRC’s CIS online service or use commercial CIS software, timely submission and payment are key. Remember: the 19th of the month is your golden date for filing, and the 22nd is for payments, miss them, and penalties will follow.

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