National Insurance for the Self-Employed: How It Works
When you work for yourself, National Insurance no longer appears neatly on a payslip. Instead it is worked out on your profits and paid through Self Assessment, alongside your Income Tax. This guide explains Class 4 and Class 2 contributions for the 2026/27 tax year, why your NI record matters for your State Pension and how to protect it if your profits are low. It is general information, not tax advice, and rates change every tax year, so check GOV.UK or an accountant.
Key takeaways
- Self-employed people mainly pay Class 4 National Insurance: 6% on profits between £12,570 and £50,270, and 2% above £50,270, for 2026/27.
- With profits of £7,105 or more, Class 2 is treated as paid, which protects your NI record without a separate bill.
- With profits under £7,105, you can choose to pay voluntary Class 2 at £3.65 a week to keep building your record.
- Most sole traders pay NI through Self Assessment, so it is included in the 31 January bill and in payments on account.
- Your NI record decides your State Pension and access to some benefits, so gaps can matter later.
National Insurance does two jobs. It is a tax on earnings, and it builds a contribution record that unlocks the State Pension and certain benefits. As an employee you hardly notice it. As a sole trader, you need to understand both sides, because what you pay and what you build are no longer automatic.
The good news is that the system for the self-employed is now simpler than it used to be. For most sole traders with reasonable profits, there is one contribution to think about, and it is calculated for you when you file your tax return.
The two classes that matter to sole traders
There are several classes of National Insurance, but self-employed people deal with two of them.
Class 4: the one you pay on profits
Class 4 is a percentage of your taxable profits from self-employment. It works in bands, a bit like Income Tax, but with its own rates. You pay nothing on profits up to the lower limit, then a main rate on the band above it and a lower rate on anything above the upper limit.
Class 2: the one that protects your record
Class 2 used to be a flat weekly charge that most sole traders paid. Today, if your profits are at or above a certain level, Class 2 is treated as paid. You do not get a bill for it, but you still get the credit on your National Insurance record. If your profits are below that level, you can choose to pay Class 2 voluntarily.
Class 4 rates for 2026/27
Here are the Class 4 bands for the current tax year, which runs from 6 April 2026 to 5 April 2027. National Insurance applies across the UK; unlike Income Tax, it does not have separate bands in Scotland. Your Income Tax bands, however, do differ if you are a Scottish taxpayer.
| Annual profits | Class 4 rate |
|---|---|
| Up to £12,570 | 0% |
| £12,570 to £50,270 | 6% |
| Above £50,270 | 2% |
These figures are for 2026/27 only. Rates and thresholds can change every tax year, so check GOV.UK before relying on them for a different year.
Example
Imagine two sole traders with made-up profits for 2026/27. The first, a copywriter, makes £30,000 in profit. Her Class 4 is 6% of £17,430 (the profit above £12,570), which is £1,045.80. Because her profit is above £7,105, Class 2 is treated as paid.
The second, a web developer, makes £60,000 in profit. His Class 4 is 6% of £37,700 (the band from £12,570 to £50,270), which is £2,262, plus 2% of £9,730 (the profit above £50,270), which is £194.60. His total Class 4 is £2,456.60.
These are simplified examples. They ignore Income Tax, other income, employment earnings and any other adjustments.
Common mistake
Budgeting only for Income Tax and forgetting National Insurance. Your Self Assessment bill includes Class 4, and so do your payments on account. If you set aside money for tax, make sure your percentage covers both.
How and when you pay
For most sole traders, National Insurance is paid through Self Assessment. You do not register for Class 4 separately or make weekly payments. The process looks like this:
- Register for Self Assessment when you start trading, if you earn more than £1,000 from self-employment in a tax year.
- Keep records of income and allowable expenses so your profit figure is accurate.
- File your return online by 31 January after the end of the tax year. The calculation works out Class 4 and shows whether Class 2 is treated as paid.
- Pay the bill by 31 January. Class 4 counts toward your payments on account, due 31 January and 31 July.
Because Class 4 is part of the figure used for payments on account, a jump in profits will push up both your balancing payment and the next year's advance payments.
Why your NI record matters
Paying National Insurance is not just a cost. Each tax year where you pay or are credited with enough contributions counts as a qualifying year on your record. Those qualifying years decide how much State Pension you get.
- You usually need 35 qualifying years for the full new State Pension.
- You usually need at least 10 qualifying years to get any State Pension at all.
- Some benefits, such as New Style Employment and Support Allowance, depend on your contributions in recent tax years.
When Class 2 is treated as paid, the year counts for your record. That is why the £7,105 profit level is important: below it, the year may not count unless you take action.
Pro tip
Check your National Insurance record and State Pension forecast through your personal tax account on GOV.UK once a year. It is the quickest way to spot a gap, for example a year when you started a business, took a break or had low profits.
Low profits: should you pay voluntary Class 2?
If your profits are below £7,105, Class 2 is not treated as paid and nothing is charged automatically. You can choose to pay voluntary Class 2 contributions at £3.65 a week for 2026/27. Voluntary Class 2 can be a low-cost way to protect your record for a year when profits are small, such as your first year of trading.
Reasons to consider voluntary Class 2
- You have no other way of getting a qualifying year for that tax year
- You are short of the qualifying years you need for a full State Pension
- You may need contribution-based benefits in the near future
- The weekly rate is low compared with other ways of filling gaps
Reasons it may not be needed
- You already get a qualifying year from a job or from National Insurance credits
- You already have enough qualifying years for the full State Pension
- Your profits will be above £7,105, so Class 2 is treated as paid
- You need the cash for essential costs and a gap can be filled later
You may already get a qualifying year in other ways, for example through employment earnings or credits linked to certain benefits or caring responsibilities. Check your record before paying, so you do not pay for a year that already counts.
Self-employed and employed at the same time
If you have a job as well as a business, you pay Class 1 National Insurance through PAYE on your salary and Class 4 through Self Assessment on your profits. The two are calculated separately. If your combined earnings are high, it is worth checking with HMRC or an accountant whether any limits on total contributions apply to you.
Planning ahead for National Insurance
Because Class 4 is calculated on your profit, the simplest way to stay on top of it is to know your profit as the year goes on, not just when you file. A few habits help:
- Track profit monthly. Bookkeeping software or a simple spreadsheet shows your running profit, so you can see which Class 4 band you are heading into.
- Save a percentage that covers both taxes. When you work out how much of each payment to set aside, include Income Tax and Class 4, not just one of them.
- Claim every allowable expense. Class 4 is charged on profit after expenses, so missed expenses mean paying more National Insurance as well as more Income Tax.
- Watch the £7,105 level in a quiet year. If your profits look likely to fall below it, for example because you took time off or started late in the year, plan whether to pay voluntary Class 2.
If you are in Making Tax Digital for Income Tax, your quarterly updates give you a regular estimate that includes National Insurance, which makes this planning easier. Either way, review the figures before 31 January so the bill holds no surprises.
Your National Insurance checklist
- Register for Self Assessment if your self-employed income is over £1,000
- Include Class 4 in the percentage you save for tax
- Check whether your profit for the year is likely to be above £7,105
- If it is below, decide whether voluntary Class 2 makes sense for you
- Review your NI record and State Pension forecast on GOV.UK once a year
- Recheck rates and thresholds at the start of every tax year
Frequently asked questions
Do I pay National Insurance if my profits are below £12,570?
You do not pay Class 4 on profits up to £12,570 in 2026/27. If your profits are between £7,105 and £12,570, Class 2 is treated as paid, so you get a qualifying year without a bill. Below £7,105, you can choose to pay voluntary Class 2.
Is National Insurance different in Scotland?
National Insurance rates and thresholds apply across the UK. Scotland has different Income Tax bands, so a Scottish sole trader's total bill can differ, but the Class 4 calculation follows the same bands.
Do I need to register separately for National Insurance as a sole trader?
Generally no. Registering for Self Assessment as self-employed is enough, and your National Insurance is worked out through your tax return. You will need your National Insurance number when you register.
Does a limited company director pay Class 4?
No. Class 4 applies to self-employed profits. Directors of limited companies are taxed differently, through the company's payroll and their personal tax position, which is a separate topic to discuss with an accountant.
Related reading
The bottom line
For most sole traders, National Insurance comes down to Class 4 on profits, paid through Self Assessment, with Class 2 treated as paid once profits reach £7,105. Save for it alongside your Income Tax, and keep an eye on your NI record so every year counts toward your State Pension.
Rates and thresholds change every tax year. This is general information, not tax advice, so check the latest figures on GOV.UK or with HMRC, and talk to an accountant if your situation is more complex.
