IR35 check Determine Employment Status for Tax

IR35 Check: Determine Employment Status for Tax

As a contractor in the UK, understanding the nuances of the revised IR35 tax legislation could be crucial for you. The IR35 checks, introduced under the new law effective from April 2021, require clients to determine your employment status.

This shift in obligation can potentially impact your net earnings and increase your administrative tasks. The uncertainty about falling within or outside the IR35 boundaries has caused significant concern and confusion among contractors.

The changes to IR35 also impact how contractors pay National Insurance Contributions (NICs). As a result, contractors need to understand what this means for them and how they can ensure compliance with the new rules. So let’s dive in!

Table of Contents

Understanding IR35 Status Determination and Compliance Regulations

What is IR35 legislation?

IR35 legislation determines the tax status of contractors and freelancers in the UK. The law was introduced to prevent workers from avoiding paying taxes by operating as a limited company but still working for a single client regularly, which would classify them as employees. Read the full article here: What is IR35? Understanding the UK’s Tax Legislation on Intermediary Workers.

How is IR35 status determined?

IR35 determinations are made to assess whether a worker is an employee or self-employed. The determination considers several factors such as control, substitution, and mutuality of obligation. Control refers to how much control the client has over the work being done. Substitution refers to whether the worker can send someone else in their place to do the work. Mutuality of obligation refers to whether there is an ongoing obligation between both parties.

Why is compliance with IR35 rules essential?

Compliance with IR35 rules is essential for businesses to avoid penalties and legal issues. If HMRC determines that a contractor should have been classified as an employee under IR35, then they may be liable for unpaid taxes and national insurance contributions. Businesses that fail to comply with IR35 regulations can face significant financial penalties.

How can you ensure IR35 compliance?

Understanding IR35 status and compliance regulations is crucial for both contractors and businesses. Here are some steps you can take:

  1. Conduct an IR35 check: Use HMRC’s Check Employment Status for Tax (CEST) tool or seek professional advice from an accountant or tax specialist.
  2. Review contracts: Ensure that your contract accurately reflects the working arrangement between both parties.
  3. Keep records: Maintain accurate records of your working practices.
  4. Seek professional advice: Consult with professionals specialising in employment law or taxation if you have any questions about your status.

The HMRC Check Employment Status for Tax Tool: An Overview

What is the HMRC Check Employment Status for Tax Tool?

The HMRC Check Employment Status for Tax (CEST) Tool is a free online service HM Revenue and Customs provides. The tool helps individuals and organizations determine a worker’s employment status for tax purposes. It considers various factors such as control, substitution, and mutuality of obligation.

How does the CEST tool work?

The CEST tool provides a view on whether a worker should be considered employed or self-employed for income tax and national insurance contributions. It asks a series of questions about the working arrangement between the organization and the worker, including details about their contract, working hours, and responsibilities.

Once all of the questions have been answered, the tool will provide an employment status determination based on its assessment of the working arrangement. This determination can be used to help organizations decide how much tax they should deduct from workers’ paychecks.

Why use the CEST tool?

Using the CEST tool can help organizations ensure that they are complying with IR35 legislation. If an organization incorrectly categorizes a worker’s employment status, it may be liable to pay additional taxes or face penalties from HMRC.

By using the CEST tool, organizations can assess a worker’s employment status accurately, reducing their risk of non-compliance with IR35 legislation.

How do I access the CEST tool?

The CEST tool is available on the website. To access it, simply search for “Check Employment Status for Tax” in your preferred search engine or visit

Who Needs to Conduct an IR35 Check?

IR35 is a set of tax rules that apply to contractors and freelancers who work for clients via an intermediary, such as a limited company. The rules are designed to prevent workers from avoiding taxes using this structure. Here are some key points about who needs to conduct an IR35 check.

Businesses that hire contractors or freelancers need to conduct an IR35 check.

If you own or manage a business that hires contractors or freelancers, it’s your responsibility to determine whether the worker falls inside or outside of IR35. If they fall inside, you’ll need to deduct Income Tax and National Insurance contributions from their pay, just like you would for an employee. If they fall outside, they’ll be responsible for paying their own taxes.

Contractors who provide services through a limited company need to conduct an IR35 check.

If you’re a contractor who provides services through a limited company, it’s your responsibility to determine whether your contract falls inside or outside of IR35. You can use HMRC’s online tool called CEST (Check Employment Status for Tax) to help you make this determination.

Public sector organizations are required by law to conduct an IR35 check on all contractors.

Since April 2017, public sector organizations have been required by law to determine the employment status of every contractor they engage with. This means that if you’re a contractor working in the public sector, your client will assess your status and tell you whether you fall inside or outside of IR35.

Private sector organizations must conduct an IR35 check starting April 2021.

From April 6th, 2021, medium and large private sector organizations will be responsible for determining the employment status of every contractor they engage with. This means that if you’re a contractor working in the private sector, your client will assess your status and tell you whether you fall inside or outside of IR35.

How to Use the HMRC CEST Tool for IR35 Compliance

What is the HMRC CEST tool?

The HMRC Check Employment Status for Tax (CEST) tool is a free online tool that helps determine the employment status of contractors for IR35 compliance. It was introduced by HM Revenue and Customs (HMRC) in 2017 to help businesses and contractors determine whether their contracts fall inside or outside of IR35 legislation.

How does it work?

The CEST tool asks a series of questions about the contractor’s working arrangements, such as:

  • Does the contractor have control over how they complete their work?
  • Is there a right of substitution?
  • Is there an obligation on the client to provide work?
  • Who provides the equipment and materials needed to do the job?

Based on these answers, the tool provides a determination at the end, stating whether or not IR35 rules apply to that specific engagement.

Why use it?

Although using the CEST tool is not mandatory, it can be used as evidence of reasonable care in an IR35 investigation. This means that if HMRC investigates you for using contractors, you can show that you took steps to ensure compliance with IR35 legislation by using this tool.

It’s important to note that while using this tool can be helpful, it doesn’t guarantee compliance with IR35 regulations. The determination provided by CEST is based on responses given by users and may not reflect all aspects of an individual engagement.

Tips for accurate results

It’s important to answer all questions truthfully and accurately to get an accurate determination from the CEST tool. Some tips include:

  • Make sure you understand all questions before answering them.
  • Consider seeking legal advice if you’re unsure about your engagement.
  • Provide detailed answers where possible.
  • Keep records of your answers in case they are needed in future investigations.

Working Practices: Employee or Self-Employed Entity?

Working practices play a crucial role. In the context of IR35, payroll working practices are essential in determining the employment status of workers.

Understanding Working Practices

Working practices refer to how work is carried out by a person within a company or business. It includes factors such as the level of control exercised over the worker, the type of work performed, and who provides the necessary tools and equipment.

Importance of Payroll Working Practices

Payroll working practices are critical when determining employment status for IR35. If a worker is deemed an employee for tax purposes, their income will be subject to PAYE (Pay As You Earn) deductions from their salary. On the other hand, if they are considered self-employed entities, they will pay taxes through self-assessment.

Guidelines Set by Revenue

The Revenue has strict guidelines on working practices to determine the employment status of public sector workers. They have developed an online tool called Check Employment Status for Tax (CEST), which helps companies and agencies determine whether their workers fall under IR35 regulations.

Factors Affecting Employment Status

Several factors can affect whether a worker is classified as an employee or self-employed entity:

  • Control: If the company exercises significant control over how and when work is done, it suggests that the worker may be an employee.
  • Substitution: If a person can send someone else to do their job without seeking permission from their employer, it suggests that they are self-employed.
  • Financial Risk: If a person bears financial risk related to their work rather than being paid a fixed salary or hourly rate, they are more likely to be considered self-employed.
  • Equipment and Tools: If a person provides the equipment and tools needed for work rather than being provided by their employer, it suggests that they are self-employed.

Contract of Service or Contract for Services? Which One Applies to You?

Understanding the Difference

Understanding the difference between a Contract of Service and a Contract for Services is crucial. The decision on which contract applies to you depends on your relationship with the client or agency and the terms of engagement.

A Contract of Service implies an employer-employee relationship. In this type of contract, the employer controls when, where, and how work is done. Conversely, a Contract for Services indicates a self-employed contractor-client relationship. In this type of contract, the contractor has more autonomy over completing their work.

Determining Your Status

The law does not provide a clear-cut answer on which contract to use since it depends on the specific situation and case. However, answering several questions regarding your engagement can help determine which contract applies to your situation.

  1. Who has control over how work is done?
  2. Is there an obligation for personal service?
  3. Can you send a substitute if unable to perform work?
  4. Is there financial risk involved in completing work?
  5. Is there equipment provided by either party?

Answering these questions will give you an idea of whether you are considered an employee or self-employed under IR35 regulations.


If you are deemed an employee under IR35 regulations, then taxes will be deducted from your pay at source by either the client or agency that pays you. On the other hand, if you are classified as self-employed under IR35 regulations, then it is up to you to calculate and pay any taxes due.

It’s important to note that even if your contract states that you are self-employed, HMRC may still classify you as employed under IR35 regulations if they believe that your working practices suggest otherwise.

IR35 Check: When Do the IR35 Rules Apply?

New Rules Effective from April 2021

From April 6, 2021, the new IR35 rules will apply to medium and large companies in the UK. The changes were initially due to take effect in May 2020 but were postponed for a year due to the COVID-19 pandemic.

The new rules are designed to ensure that contractors working through their limited company broadly pay the same tax and National Insurance contributions as an equivalent employee. Under these changes, it is now up to companies, rather than contractors themselves, to determine whether or not they fall inside or outside of IR35.

Companies Must Determine Employment Status

Companies must conduct an “IR35 check” on every contractor they engage with. This means assessing whether each contractor would be deemed an employee if directly engaged by the company. If so, income tax and NICs should be deducted at source from payments made to that contractor.

To make this determination, companies need to consider various factors such as control over how work is done and who does it; financial risk; benefits provided; and integration with the organization’s operations.

Penalties for Non-Compliance

There could be serious consequences if a company fails to comply with these new rules or makes incorrect determinations about a contractor’s employment status. The fees can include unpaid taxes plus interest and penalties which could amount up to tens of thousands of pounds per engagement.

Businesses must take steps now to ensure compliance with these new regulations before they come into effect in April 2021.

Additional Resources for IR35 Assessment

Why take this assessment?

As a contractor or freelancer, it’s essential to determine your employment status for tax purposes. This determination will help you understand whether you fall inside or outside the scope of IR35 legislation.

IR35 is a set of rules that apply if you work for a client through an intermediary such as a limited company, and HMRC considers you to be an employee in all but name. If IR35 catches you, you must pay income tax and National Insurance contributions as employed.

To help make this determination easier, there are several resources available:

Online IR35 Assessment Tools

Online assessment tools can provide quick and easy assessments of your employment status. These tools use questionnaires to determine whether your working arrangements fall inside or outside the scope of IR35.

One such tool is the Check Employment Status for Tax (CEST) tool provided by HMRC. CEST is free to use and provides an instant result based on your responses to a series of questions about your working arrangements.

While CEST is not perfect and has faced criticism in the past, it’s still worth using as a starting point for assessing your employment status.

Seeking Professional Advice

If you want a more detailed and accurate assessment of your employment status, seek professional advice from an accountant or tax expert.

An experienced advisor can review your contract and working practices to assess whether they comply with IR35 legislation. They can also advise on any changes that need to be made to ensure compliance with the rules.

While seeking professional advice may come at a cost, it can save you money in the long run by ensuring that you’re correctly classified under IR35 legislation.

The Importance of Conducting an IR35 Check

In conclusion, conducting an IR35 check is crucial for individuals and businesses to ensure compliance with the regulations set out by HMRC. Understanding the status determination process and utilizing the HMRC CEST tool can help determine whether working practices align with employment or self-employment status. It is important to accurately identify whether a contract is one of service or for services to avoid potential legal and financial consequences.

Those who need to conduct an IR35 check must do so promptly, as failure to comply with regulations can result in penalties and legal action. Additional resources such as professional advice and case studies can provide further insight into navigating the complexities of IR35.

To ensure compliance, it is recommended that individuals and businesses regularly review their working practices, contracts, and employment status determinations. Individuals and businesses can avoid costly penalties and legal action by taking proactive steps towards understanding and complying with IR35 regulations.


1. Who needs to conduct an IR35 check?

Individuals who work through their own limited company or operate as a sole trader must determine their employment status for each contract they undertake. Businesses that engage contractors must also conduct an assessment to determine whether they fall within the scope of IR35.

2. What are the consequences of failing to comply with IR35 regulations?

Failure to comply with IR35 regulations can result in significant financial penalties, including backdated taxes, interest charges, and fines from HMRC. Legal action may also be taken against those found non-compliant.

3. How often should I conduct an IR35 check?

It is recommended that individuals and businesses regularly review their working practices, contracts, and employment status determinations on an ongoing basis rather than waiting until a specific deadline or event occurs.

4. Can I use alternative tools besides HMRC’s CEST tool for determining my employment status?

Determining your employment status can be a complex and challenging process. While there are many tools and resources available to help you with this task, it is important to choose carefully and ensure that the information you receive is accurate and reliable.

One of the most popular methods for determining employment status is the IR35 check, designed to help contractors and freelancers understand whether they are operating as genuine self-employed individuals or are actually employees in the eyes of HMRC.

However, while the IR35 check can be a useful tool, it is not always 100% accurate, and it may be necessary to seek professional advice to fully understand your employment status and comply with relevant tax laws. Consulting with an experienced accountant or tax specialist can help you navigate the complexities of employment status, ensure that you are paying the correct amount of tax, and avoid any potential legal or financial issues down the line.

Understanding your employment status and complying with relevant regulations is essential for anyone working as a contractor or freelancer in today’s economy.