How to Calculate CIS Tax in the UK

In the United Kingdom, contractors and subcontractors within the construction industry navigate a unique taxation system called the Construction Industry Scheme (CIS). Understanding how to calculate CIS tax is crucial to ensure compliance and accurate payments. Here is a step-by-step guide to calculating CIS tax in 2023.

Understanding CIS Tax

The CIS is a tax scheme wherein contractors deduct money from subcontractors’ payments and pass it to HM Revenue and Customs (HMRC). These deductions act as advance payments towards the subcontractor’s tax and National Insurance. There are several types of CIS calculations including 30%, 20%, and 0% tax rates​​.

CIS Tax Deductions: The deduction rates are usually as follows:

  1. 20% for registered subcontractors
  2. 30% for unregistered subcontractors
  3. 0% if the subcontractor has ‘gross payment’ status, which means they do not have deductions made from their payments

Necessary Information for CIS Calculation

To complete a CIS calculation, three pieces of information are required:

  1. Gross Amount: This is the total invoiced amount. If the subcontractor is VAT registered, the contractor should exclude VAT from the total.
  2. Qualifying Materials: These are the costs that the subcontractor has incurred. For instance, a decorating subcontractor would recharge the paint they have purchased.
  3. CIS Tax to Deduct: The contractor deducts the qualifying materials from the gross amount, which gives a labour amount. Then, the contractor calculates the tax to deduct by applying the CIS tax rate to the labour amount.

Determining Subcontractor CIS Status

The first step in calculating CIS tax is determining the subcontractor’s CIS status. The CIS tax rate that contractors apply depends on this status. The subcontractor’s status can be one of three options: gross, net, or not registered​​. The HMRC provides the deduction tax rate, determined when completing the subcontractor verification​​.

Accounting for VAT and Identifying Costs

Next, consider the Value Added Tax (VAT) rate charged. The subcontractor’s invoice should clearly state this rate. Be aware that in the construction industry, some invoices are treated with a reverse VAT. If you’re unsure if this applies, seek advice or use an online tool designed to clarify this point​.

Furthermore, it’s essential to correctly identify and split the labour and materials cost in the invoice. Unless the subcontractor is registered with gross payment status, their invoice must clearly separate these costs. When calculating CIS tax, only enter qualifying materials in the materials box. Non-qualifying costs such as travel or accommodation fees should be added to the labour value​.

CIS Tax Calculation for VAT Registered Subcontractors

Consider a scenario where the subcontractor is both CIS and VAT registered. The contractor has received an invoice from the subcontractor with the following details:

  • Labour: £500 + VAT £100
  • Materials: £200 + VAT £40
  • Total Invoiced: £700 + VAT £140

The figures to report to HMRC are:

  • Gross Amount: £700 (total amount invoiced excluding VAT)
  • Qualifying Materials: £200 (qualifying materials per the invoice excluding VAT)
  • CIS Tax to Deduct: £100 (calculated as the gross amount of £700 less the materials of £200, giving a figure of £500 which is then multiplied by the CIS tax rate of 20%)

The contractor would therefore pay HMRC CIS Tax of £100 and the subcontractor £740.

CIS Tax Calculation for Non-VAT Registered Subcontractors

Now, let’s consider a scenario where the subcontractor is not VAT registered. The invoice would look as follows:

  • Labour: £500
  • Materials: £240
  • Total Invoiced: £740

The figures to report to HMRC are:

  • Gross Amount: £740 (total amount invoiced – no VAT has been charged so none is deducted)
  • Qualifying Materials: £240 (qualifying materials per the invoice)
  • CIS Tax to Deduct: £100 (calculated as the gross amount of £740 less the materials of £240, giving a figure of £500 which is then multiplied by the CIS tax rate of 20%)

The contractor would therefore pay HMRC CIS Tax of £100 and the subcontractor £640.

Finalizing the Calculation

After entering the necessary figures, cross-check to ensure that the Net, VAT, and Gross figures match the invoice. The CIS tax deduction calculator will then work out the CIS tax to deduct. This amount is payable to HMRC in your monthly return.

The final figure is the amount to pay to the subcontractor. If CIS tax has been deducted, the contractor must provide a payment and deduction statement to the subcontractor​​.

Calculating CIS tax doesn’t need to be a daunting task. With the right tools and information, contractors can efficiently manage their obligations and maintain compliance. As the nuances of tax law often change, it’s vital to stay updated with the most recent regulations, like those outlined for 2023. For complex situations, consider seeking professional advice to ensure accurate calculations and compliance with the law.

CIS Tax Deduction Calculator

CIS Tax Deduction Calculator

Why is it a Good Idea to Get Professional Help from a Tax Accountant

Handling tax affairs, especially in a complex regulatory environment like the UK, can be an intricate process for individuals and businesses. This is particularly true for those in the Construction Industry Scheme (CIS), where tax procedures can be quite challenging to navigate. Professional help from a tax accountant, such as Total Tax Accountant, can provide valuable assistance in these matters.

Specialized Knowledge of CIS Tax

CIS tax is a specialized area of taxation. It comprises a series of regulations that apply to contractors and subcontractors in the construction sector. Tax accountants, specifically trained in this field, possess an in-depth understanding of these rules and are well-equipped to help you navigate the intricacies of CIS tax. They can ensure full compliance, reduce risks of penalties, and identify potential tax savings that you may otherwise overlook.

Accuracy and Compliance

Given the strict regulatory framework in the UK, any errors in tax calculation or filing could lead to penalties and legal issues. Professional tax accountants like Total Tax Accountants bring accuracy to the table. They can help you avoid mistakes that may have serious financial and legal implications. Moreover, they stay updated with the ever-changing tax legislation, ensuring your tax affairs always adhere to the current laws.

Time and Resource Savings

One cannot overlook the time-consuming nature of tax management. From understanding the nuances of the tax code to completing the paperwork, these tasks can divert you from focusing on your core business. By outsourcing tax work to professionals, you save valuable time and resources. These savings can then be invested back into the business, promoting growth and development.

Financial Planning and Advice

Professional tax accountants offer more than just compliance. They can provide tailored financial advice, help plan your taxes efficiently, and identify possible tax deductions or credits. Such proactive financial planning can have long-term benefits, allowing you to minimize tax liability and increase your overall financial health.

Help with Audits

Tax audits can be stressful and demanding. If you find yourself facing one, having a professional tax accountant by your side can make a significant difference. They can guide you through the process, represent you in discussions with tax authorities, and ensure your rights are protected.


In the context of CIS tax in the UK, getting professional help from a tax accountant is not just a good idea—it’s an excellent one. It leads to accurate and efficient tax management, safeguards against penalties and audits, and provides strategic advice for financial growth. A tax accountant, like Total Tax Accountant, ensures your peace of mind by taking on the complexity of tax tasks, leaving you to focus on what you do best – running your business.