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National Insurance Calculator

Created by Wei Bin Loo
Reviewed by Dominik Czernia, PhD and Adena Benn
Last updated: May 25, 2024

With this national insurance calculator, we aim to help you to calculate the amount of national insurance you have to pay working in the UK.

We have written this article to help you understand what national insurance is, what your national insurance rates are in the UK and how to calculate your national insurance. We will also demonstrate some calculation examples to help you understand the process.

What is national insurance?

The national insurance is the money you have to pay from your salary to entitle yourself to the state welfare. It is the UK version of social security.

The national insurance contributions are collected by the HM Revenue and Customs (HMRC). You need to make the national insurance contributions for at least 25 years to be entitled to retirement payment from your national insurance account.

How to use our national insurance and tax calculator

We have built our national insurance and tax calculator to be very easy to use. All you need to do is the following three steps:

  1. Calculate your total annual income

    The first step is to calculate your total annual income. You can calculate this using the following formula:

    total annual income = employment income + self employment net income

    The self-employment net income should include money coming from rental, freelancing, etc.

  2. Determine the tax year that you are looking at

    Every year, the UK government makes some changes to the amount of National Insurance that they charge. Thus, it is essential that you select the correct tax year that you want to calculate. The default tax year has been set to the most recent one, but please feel free to change it to an earlier tax year if that is what you are calculating.

  3. Understand your national insurance

    You should now see the national insurance that you need to pay calculated by our national insurance calculator.

    If you are not self-employed, you will only need to pay the Class 1 National Insurance. Self-employed people are legally required to pay both the Class 2 and Class 4 National Insurance.

How much national insurance do I pay and how is national insurance calculated?

The national insurance calculation is relatively easy to understand compared to other tax schemes. Parties that need to pay national insurance are:

  • Employees;
  • Self-employed people; and
  • Companies.

As self-employment has different national insurance rates, let's discuss them separately. First, let's look at people who are not self-employed.

  • If you are not self-employed, you don't need to pay any national insurance for the first £11,904 you earned. Then, you will need to pay 13.25% (12% before the national insurance rise in the tax year 2022/23) for the money you earned above £11,904 and below £50,270. Finally, you will need to pay 3.25% for anything you earned above £50,270.

  • If you are self-employed, the rates applied to your national insurance are slightly different. You don't need to pay national insurance for the first £6,725 you earned. For money you earned from £6,725 to £9,568, you will need to pay a flat national insurance of £163.80. For money you earned above £9,568, and below £50,270, you will be paying 10.25% (9% before the national insurance rise in the tax year 2022/23) for the national insurance. Similar to people who are not self-employed, you also need to pay 3.25% for anything you earned above £50,270.

  • Lastly, companies also need to pay national insurance for their employees. Although this might not impact you as this is not the money you will be paying, it is good to know that your employers are also required to contribute to your national insurance scheme. In general, employers are required to contribute 15.05% of their employees' salary as national insurance.


What is a national insurance number?

The National Insurance Number is your personal tax account number. It is used to make sure your tax is paid only under your name.

Can the national insurance be negative?

No, the national insurance cannot be a negative number as a negative national insurance would mean that the government pays you tax.

What factors affect my national insurance?

Your national insurance is affected by your:

  • Employment status, i.e., whether you are self-employed or not
  • Annual income
  • Companies also need to pay national insurance for their employees

Do I pay National Insurance if I earn less than the Personal Allowance?

Yes, even if you earn less than £12,570, you will still have to make your national insurance contributions.

What is my national insurance if I my annual income is 48000?

Assuming that you are not self-employed, your national insurance would be: £4782.72
If your annual income is £48,000, you can calculate your national insurance by:

  1. Subtracting £11,904 from £48,000 = £36,096.
  2. Find 13.25% of £36,096 = £4,782.72.

How do I calculate my total annual income?

You can calculate your total annual income using the following steps:

  1. Determine your employment income
  2. Determine your self-employment net income
  3. Apply the total annual income formula: total annual income = employment income + self-employment net income
Wei Bin Loo
Annual income
Employment income
Self employment net income
Total annual income
National Insurance
Tax year
2022 / 2023
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