If you’re reassessing your career path but you’re not quite ready to quit your regular job yet - you’ve come to the right place. This bumper article contains a wealth of handy information about how to kickstart a freelance career while balancing a regular full-time job.

We’ve previously written about how you can start a business while still working. This can be a good way to reduce the risks of setting up a business to still have some income coming in. And, contrary to popular belief, the terms ‘employed’ and ‘self-employed’ are not opposites. 

In the strange world of HMRC, it’s possible to be employed and self-employed at the same time – in fact, it’s actually pretty common. Many people first dip their toes into the world of being self-employed by freelancing on the side. However, employed and self employed tax is recorded and reported via different systems, so it’s important you understand your obligations. 

If you’re considering making a bit of extra money by freelancing on top of your main job, read on for everything you need to know, including what self-employed tax and National Insurance you’re expected to pay, and how to pay them.

How much income tax will I pay as a sole trader freelancer?

In virtually all cases, employees are paid through the PAYE system, where their tax is calculated and paid automatically. Any income you make through self-employment or freelancing, however, falls outside of that wrapper and becomes untaxed income. The duty for paying tax is as follows:

• Employer: your workplace should calculate and deduct the appropriate taxes for all income related to your salary. This also includes Class 1 National Insurance payments. 
• You: as a self-employed person, you need to record total income and then work out profit minus expenses. You’ll be taxed on profits and will also have to pay Class 4 National Insurance contributions and potentially Class 2 if you wish to make voluntary contributions.

To calculate how much tax you need to pay, you’ll need to register for Self-Assessment and submit a tax return to declare your income. The amount of income tax you have to pay is calculated separately through this system, which also means you can claim for allowable expenses to reduce your tax liability. 

If you’re both employed and a self-employed freelancer, tax can be tricky – but as long as you’re accurately recording income from self-employment and following the guidelines for Self-Assessment, you should be fine. 

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Let’s look at an example to see how you calculate and pay tax as an employee AND sole trader… 

Working out income tax: an example for 2025/26

Your Income Tax is always calculated on total earnings, so you’ll have to pay tax on amounts above the Personal Allowance for your combined income from employment and sole trader profits (from freelancing). It’s important to realise that if your sole trader profits push your total earnings into a higher tax band, you’ll have to pay the higher rate.

Remember: your employer will automatically deduct tax from your income related to employment – so you’ll have to inform HMRC during Self-Assessment and they’ll work out the appropriate income tax minus the employment tax you have already repaid. 

The best way to explain how the system works is through an example. Let’s take a detailed look at how you calculate your TOTAL income tax liability using the figures HMRC publishes to determine rates and thresholds for the 2025/26 and 2024/25 tax years.

Imagine you’re earning £35,000 as a salaried employee, and £20,000 as a sole trader. In each tax year, your income tax can be worked out as follows:

* There are different income tax rates for Scottish residents

You’ll pay Income Tax of 20% on all earnings above your personal allowance and below the upper limit of the basic rate, which is £37,700 for the 2025/26 and 2024/25 tax years. 

You’ll pay Income Tax of 40% on all earnings above the basic rate limit until you reach the higher rate limit (which in the 2025/26 and 2024/25 tax years is/was £125,140). In this example, you pay 40% tax on income of £4,730 in the 2025/26 and 2024/25 tax years, due to the higher thresholds.

When you prepare your annual Self Assessment tax return, you will disclose the tax already paid on your earnings from your employer (in this example £35,000 would have been taxed under PAYE arrangements). So HMRC will know you have already paid tax on part of your total income. 

The amount of tax you pay on your profits from self-employment (£20,000 in this example) will be worked out by HMRC when you submit your Self Assessment. You can find out more about how to complete your first Self Assessment in our handy article, or watch the video below to see how we can help you make yours a doddle

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What about National Insurance?

The National Insurance you pay on your income from your employer won’t change, but it’ll be a bit different for your income from self-employed profits. Class 2 National Insurance was £3.45 per week in 2023/24 but has been discontinued as of April 2024/25, so it’s no longer relevant unless voluntary contributions are made. 

However, you may have to pay Class 4 National Insurance, which has been reduced from 8% to 6% in the 2025/26 year. 

For the 2024/25 tax year, this is charged at 8% for all self-employed profits between £12,570 and £50,270, and at 2% for all profits greater than £50,270. In the 2025/26 year, this drops to 6% and 2%. Just like your Income Tax, Class 4 National Insurance contributions will be worked out on your Self Assessment tax return.

To work it out, let’s look at our earlier example where sole trader profits were £20,000: 

• First you need to work out what profits fall within the threshold – so subtract £20,000 from £12,570 to get £7430.
• From the 2024/25 tax year, class 2 is being scrapped, so only Class 4 NICs apply at 6%. 6% of £7430 gives you a total payment of £445.80. 

Remember, you’ll have your Class 1 National Insurance as an employee to pay too, this is paid through PAYE deductions made by your employer for your paid employment, you can find details on the Gov.uk website.

Sole Trader or Limited Company?

As a self-employed person, you can choose to operate as a Sole Trader, or form your own Limited Company.

The basic difference is that if you’re a sole trader freelancer, then there’s no legal separation between you and your business. You’re personally liable for all activities of the business, including debts.

If you form a limited company to freelance then you create a separate legal entity and have no personal liability. However, you’ll have specific legal and statutory responsibilities to fulfil as a director of the company. This also has a number of tax implications.

Read more about the differences between sole traders and limited companies.

What about expenses?

One of the main benefits of registering as self-employed as a sole trader is that you get to offset your business expenses against your income. You’re only taxed on your self-employed profits.

There’s a similar situation for limited companies - where Corporation Tax is only paid on company profits calculated after allowable expenses. These can include salary and pension contributions as well as certain travel and subsistence expenses. 

What exactly is considered to be an allowable expense and how to claim it is a complicated affair, so we won’t get into that here. Instead, visit this guide to what expenses can I claim as a sole trader to learn more. 

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The Crunch Personal Tax Estimator

The Crunch Personal Tax Estimator can help you to plan for the tax you may have to pay on your personal income including sole trade income, salary and dividends if applicable. You can read our Personal Tax Estimator article and download our calculator to try it out.

When should I tell HMRC?

Although your employer doesn’t need to know, the taxman definitely does! HMRC recommends that you let them know as soon as you start trading from your new business.

It’s a legal requirement to register with HMRC as a new business if your earnings as a self-employed sole trader are more than £1,000 in a tax year. And this includes selling on ecommerce platforms like eBay or Etsy, so make sure to factor that in too!

If you’re already employed full-time, this may happen as soon as you receive your first self-employed income. Once you’ve earned more than £1,000, you’ll have until 5th October after the end of the tax year to register as self-employed and register for your annual Self Assessment, or risk paying a fine. 

However, if you are unlikely to earn over £1,000, you don’t need to file a Self Assessment as HMRC offers the £1,000 trading allowance to remove the need for filing a return in such circumstances.

Will my employer find out about my employed and self-employed tax status?

Although it usually won’t be a problem, it’s understandable that you might not want your employer to know that you’re working on other projects. Be careful, though, because your employment contract might forbid you to take on outside work, especially if there is a risk of competition with your current employer.

Your tax affairs are entirely confidential and HMRC won’t inform your employer if you also register as self-employed. However, be aware that if you form a limited company your details are publicly available at Companies House, so your employer could find out about your business that way.

Of course, we’d never recommend that you mislead your employer. However, it’s possible to start outside work without disclosing it. Just be aware that you do so at your own risk. Read our guide to setting up as a sole trader to get started.