.png)
Does My Tax Return Bill Include National Insurance?
If you're self-employed and completing a Self Assessment tax return, you might look at the final amount HMRC says you owe and wonder: does my tax bill already include National Insurance, or do I need to pay that separately?
For most self-employed people, the simple answer is yes – any Class 4 National Insurance you owe is calculated through your Self Assessment and forms part of the overall amount you pay to HMRC.
However, not everyone completing a tax return will need to pay National Insurance through Self Assessment. Here's how it works.
What Can Be Included in a Self Assessment Tax Bill?
Your Self Assessment tax return takes into account the different sources of income that need to be reported to HMRC, which could include:
- Self-employed income and profits
- Employment income
- Dividends
- Rental income
- Pension income
- Savings and investment income
- Other taxable income
HMRC then uses the information on your return to calculate what you owe.
Depending on your circumstances, your final Self Assessment calculation could include Income Tax, Class 4 National Insurance and student or postgraduate loan repayments, as well as other amounts due.
When Is National Insurance Included?
If you're self-employed, you may have to pay Class 4 National Insurance based on your taxable profits.
For the 2026/27 tax year, Class 4 National Insurance is payable when your self-employed profits are more than £12,570.
The rates are:
- 6% on profits between £12,570 and £50,270
- 2% on profits above £50,270
Most self-employed people pay any Class 4 National Insurance due through Self Assessment.
This means you don't normally receive a completely separate Class 4 National Insurance bill – it forms part of the amount calculated through your Self Assessment.
What If I'm Employed as Well as Self-Employed?
This is where it can become confusing.
If you're employed, your employer will normally deduct Class 1 National Insurance from your salary through payroll.
If you also run a self-employed business, you may additionally have Class 4 National Insurance to pay on your self-employed profits.
Your tax return takes your circumstances into account when calculating the amount due through Self Assessment.
What About Landlords?
Simply receiving rental income doesn't necessarily mean you'll pay National Insurance on it.
There are different National Insurance rules for landlords, so whether NI applies will depend on your individual circumstances and the nature of your property activities.
You could therefore have Income Tax to pay on rental profits through Self Assessment without having Class 4 National Insurance to pay on that income.
How Can I See What I'm Actually Paying?
Your tax calculation should provide a breakdown of the amounts due rather than simply presenting one unexplained figure.
For example, it might show:
These figures are purely an example and aren't based on current tax calculations.
If Blue Rocket Accounting prepares your tax return, we'll explain your calculation so you understand what you owe, why you owe it and when it needs to be paid.
Why Is My January Bill Higher Than I Expected?
This is another common source of confusion.
Your January payment may not simply be the outstanding amount for the tax year you've just reported. You may also have to make a payment on account towards your next Self Assessment bill.
Payments on account normally apply unless:
- your previous year's relevant Self Assessment bill was less than £1,000; or
- more than 80% of the tax you owed was already collected outside Self Assessment.
If payments on account apply, you normally make two payments, with each equal to half of the relevant previous year's bill.
The first is due on 31 January and the second on 31 July.
So, for example, if the relevant amount due through Self Assessment was £4,000 and you hadn't previously made payments on account, you could potentially need to pay:
£4,000 – your tax bill
+ £2,000 – your first payment on account
= £6,000 due in January
You'd then usually pay another £2,000 in July towards the following year's bill.
It's important to remember that this isn't an extra tax charge. The payments on account are advance payments towards your next bill.
Do Payments on Account Include National Insurance?
If you're self-employed, Class 4 National Insurance can form part of the calculation used for your payments on account.
This is another reason the amount you're asked to pay in January can sometimes be considerably higher than expected.
Certain amounts, including Capital Gains Tax and student loan repayments, aren't included when HMRC calculates payments on account.
Don't Just Look at the Final Number
The most important thing is to understand what makes up your Self Assessment bill.
Your total could potentially include Income Tax, National Insurance, student loan repayments and a payment on account towards the following year.
That's why receiving a figure from HMRC without understanding the calculation behind it can be confusing – particularly if your January payment is much larger than expected.
Need Help Understanding Your Tax Bill?
At Blue Rocket Accounting, we don't believe you should be left staring at a tax calculation wondering what it means.
We help self-employed business owners, landlords, higher-earning PAYE employees and others with their Self Assessment tax returns, ensuring they're completed correctly while helping clients understand what they owe and why.
And if you have a question, you can ask us. Blue Rocket clients have a dedicated team with direct access via mobile and WhatsApp, with unlimited support whenever they need us.
If you're based in Dartford, Bexley, Erith, Crayford or the surrounding areas and would like expert help, then contact us now.
This article provides general information based on HMRC guidance and tax rates available at the time of writing. Your tax and National Insurance position will depend on your individual circumstances.
