National Insurance is one of those self-employed costs that often gets pushed to the back of your mind until your Self Assessment tax return is due. You may know you need to pay Income Tax, but National Insurance can feel less clear, especially because the rules for sole traders have changed in recent years.
If you work for yourself, your National Insurance depends on your profits, not your total sales. That means you first deduct your allowable business expenses, then HMRC looks at what is left. For many sole traders, this is where confusion starts, because turnover, profit, tax and National Insurance are all slightly different things.
In 2026/27, the main National Insurance rules for self-employed workers are more straightforward than they used to be, but they still need to be understood properly. If you want clear support from an accountant for sole trader businesses, it is worth getting your records organised before the tax return deadline arrives.
What National Insurance means when you are self-employed
National Insurance contributions help protect your entitlement to certain state benefits, including the State Pension. When you are employed, National Insurance is usually deducted from your wages through PAYE. When you are self-employed, it is normally dealt with through your Self Assessment tax return.
As a sole trader, you are usually concerned with 2 types of National Insurance:
- Class 2 National Insurance, which is linked to protecting your National Insurance record.
- Class 4 National Insurance, which is paid on self-employed profits above the lower profits limit.
You do not need to calculate everything manually if your records are clean and your tax return is prepared correctly. However, it is still useful to understand how the figures work, so you are not surprised by the final bill.
Working with a self-employed accountant can help you see the full picture across income, expenses, tax and National Insurance, rather than only thinking about the numbers once a year.
Need Help With Your Accounts Or Tax?
Whether you need support with self assessment, VAT returns, payroll, bookkeeping, CIS, company accounts or corporation tax, Asmat & Co Accountants can provide clear, practical advice for your business or personal finances.
Class 2 National Insurance in 2026/27
For the 2026/27 tax year, if your self-employed profits are £7,105 or more, Class 2 contributions are treated as paid. This means you do not have to physically pay Class 2, but your National Insurance record is still protected.
If your profits are below £7,105, you do not have to pay Class 2. However, you can choose to pay voluntary Class 2 contributions at £3.65 per week for 2026/27. This can be worth considering if you want to avoid gaps in your National Insurance record.
This is especially important if your self-employed income is low, irregular or only part of your overall income. For example, you may have started a new business, reduced your working hours, or taken time away from trading. In those situations, it is sensible to check whether voluntary contributions are worth making.
A good self-assessment tax return accountant can help you understand whether your profits protect your record automatically or whether voluntary payments may be useful.
Class 4 National Insurance in 2026/27
Class 4 National Insurance is the part most sole traders notice because it is charged on profits.
For 2026/27, you pay:
| Self-employed profit | National Insurance position |
|---|---|
| Under £7,105 | No Class 2 required, but voluntary Class 2 may be possible |
| £7,105 to £12,570 | Class 2 treated as paid, no Class 4 |
| £12,570 to £50,270 | Class 4 at 6% on profits above £12,570 |
| Over £50,270 | Class 4 at 6% up to £50,270, then 2% above £50,270 |
Here is a simple example.
If your sole trader profit is £35,000 in 2026/27, you do not pay Class 4 on the first £12,570. You pay 6% on the remaining £22,430. That gives a Class 4 National Insurance bill of £1,345.80.
If your profit is £60,000, the calculation is higher. You pay 6% on the band between £12,570 and £50,270, then 2% on the profit above £50,270.
This is why profit planning matters. Your National Insurance bill is not based on every pound you invoice. It is based on your taxable profit after allowable business expenses.
Why your records matter
National Insurance becomes harder to understand when your bookkeeping is not up to date. If you are missing receipts, mixing personal and business spending, or estimating your expenses at the end of the year, your tax position can easily become unclear.
Proper sole trader accountancy services should help you keep your records in order throughout the year, not just when the filing deadline is close.
You should keep clear records of:
- Income from your sole trader work
- Invoices sent to customers
- Business expenses
- Bank statements
- Receipts and supplier bills
- Mileage or travel costs where relevant
- Software and subscriptions
- Any other income that may need to be included in Self Assessment
Good records help you claim the right expenses, reduce mistakes and understand how much money to set aside for tax and National Insurance.
National Insurance and Income Tax are not the same thing
A common mistake is thinking National Insurance is included within Income Tax. It is not. They are separate charges, although both are usually calculated through the same Self Assessment tax return.
For England, Wales and Northern Ireland, the standard Personal Allowance is £12,570. You usually start paying Income Tax on profits above that amount, but National Insurance has its own rules and rates.
This means your final Self Assessment bill may include:
- Income Tax
- Class 4 National Insurance
- Voluntary Class 2 National Insurance, if chosen
- Payments on account, if they apply
- Student loan repayments, where relevant
This is why it is important to look at the whole tax position, not just one part of it. If you want practical sole trader accounting support, the aim should be to help you understand what you owe, why you owe it and when it needs to be paid.
When you need to register as self-employed
If you earn more than £1,000 in a tax year from self-employment, you usually need to register for Self Assessment as a sole trader. The tax year runs from 6 April to 5 April.
The £1,000 figure is based on gross trading income before expenses. So, if you invoice £1,200 but spend £300 on costs, your gross income is still £1,200.
Once registered, you submit a Self Assessment tax return each year. HMRC then calculates your Income Tax and National Insurance based on the information you provide.
If you are based locally, working with accountants in Slough can make this process easier because you have someone to help you keep things accurate, compliant and on time.
Using accounting software to stay prepared
Cloud accounting software can make a big difference for sole traders. Instead of leaving everything until January, you can keep your income and expenses updated throughout the year.
A certified QuickBooks accountant can help you set up bank feeds, categorise expenses correctly and keep your records ready for your tax return. This is particularly useful if your income changes month to month or if you want a clearer idea of how much tax and National Insurance to put aside.
Software will not replace good advice, but it can make your figures much easier to manage. It also reduces the risk of missing expenses or relying on rough estimates.
What if you have more than one source of income?
Many sole traders now have more than one income stream. You may work for yourself full time, have a side business alongside employment, receive rental income, or do freelance work alongside another trade.
This can affect your tax position. Employment income may already have National Insurance deducted through PAYE, while self-employed profits are dealt with separately through Self Assessment.
If you work across different areas, it is worth getting advice from accountants for self-employed individuals who can look at the full picture. Otherwise, you may under-save for your bill or misunderstand which income counts for which tax.
For clients outside Slough, accountants in Reading can also support sole traders and small business owners who need reliable tax and accounts guidance.
How much should you set aside?
There is no single figure that works for every sole trader, but it is usually sensible to set aside money regularly from your income. Many self-employed workers put aside a percentage of each payment they receive so the January tax bill does not come as a shock.
The right percentage depends on your profit level, expenses, other income and whether payments on account apply.
As a rough habit, it is better to save too carefully than to reach the deadline with nothing set aside. Your accountant can help you estimate your likely Income Tax and National Insurance during the year, so you are not relying on guesswork.
Why professional help can save stress
National Insurance is not usually complicated when your records are tidy and your profit is clear. The problem is that many sole traders are busy doing the work, speaking to customers, sending invoices and trying to keep cash flow steady.
That is where proper sole trader accounting services can help. You get support with your records, tax return, allowable expenses and HMRC deadlines, so you can focus on running your business with more confidence.
Frequently asked questions
Do sole traders pay National Insurance in 2026/27?
Yes, if your profits are high enough. For 2026/27, Class 4 National Insurance applies when your profits are more than £12,570. Class 2 is treated as paid if your profits are £7,105 or more.
Do I still pay Class 2 National Insurance as a sole trader?
Most sole traders no longer need to physically pay Class 2 if their profits are above the relevant threshold. If your profits are below £7,105 in 2026/27, you may choose to pay voluntary Class 2 at £3.65 per week to protect your National Insurance record.
Is National Insurance based on turnover or profit?
National Insurance is based on profit, not turnover. You calculate your profit by taking your self-employed income and deducting allowable business expenses.
Do I pay National Insurance if I have a job and a side business?
You may pay employee National Insurance through your job and self-employed National Insurance through Self Assessment if your sole trader profits are high enough. The 2 are handled differently, so it is important to check your full position.
Can an accountant help reduce my National Insurance bill?
An accountant cannot simply remove National Insurance that is legally due, but they can help make sure your profit is calculated correctly, your allowable expenses are claimed properly and your tax return is filed accurately.
If you want clear, practical help with your sole trader accounts, tax return and National Insurance, speak to Asmat & Co Accountants today. Our team can help you stay compliant, understand your numbers and plan ahead with confidence.
Need Help With Your Accounts Or Tax?
Whether you need support with self assessment, VAT returns, payroll, bookkeeping, CIS, company accounts or corporation tax, Asmat & Co Accountants can provide clear, practical advice for your business or personal finances.
