National Insurance calculator

Anyone who earns income in the UK may need to pay National Insurance (NI) - whether you're employed or self-employed.

The amount you pay will vary depending on your income and employment status. To find out how your bill is calculated, see our guide to National Insurance rates and thresholds.

You can use our calculator to work out how much your NI contributions will be in the 2024-25 tax year, but you can also use the 'Tax year' dropdown menu to select past tax years to see how your bill compares.

The figures shown (for all years apart from 2022-23 - more on this below) indicate what you'd owe on an annual basis, and assume you've worked for the full tax year. 

The calculator makes standard assumptions about employed and self-employed people to estimate your tax breakdown. So bear in mind that what you will take home also depends on other factors, such as your pension contributions and student loan repayments - and can vary depending on your tax code.

How has National Insurance changed in 2024?

The main Class 4 rate that self-employed people pay fell from 9% to 6% on 6 April.

The Class 2 flat rate that self-employed workers also used to have to pay has been scrapped for those earning over £6,725 and replaced with a credit. However, those earning below £6725 can still voluntarily pay the flat rate at £3.45 a week in 2024-25.

The Class 1 rate that employees pay has fallen from 10% to 8% on earnings over £12,570 up to £50,270.

• Our guide to National Insurance rates sets out the full rates and thresholds.

Which? tax calculator

Our jargon-free tool can help you tot up your tax bill and send your tax return directly to HMRC.

Calculate your tax bill

How do I calculate my NI bill for 2022-23 and 2023-24?

There were several changes to National Insurance rates and thresholds in 2022-23 and in 2023-24, but these have been captured in our calculator. 

To find out your total bill for 2022-23 you will need to check what you will pay between 6 April and 5 July, between 6 July and 5 November, and between 6 November and 5 April, and then add the three figures together.

How do I pay National Insurance?

If you're an employee, National Insurance will be deducted from your salary before you receive it, along with any income tax. You can work out your deductions with our income tax calculator.

If you're self-employed, you'll usually need to pay via your self-assessment tax return.

To get a head-start on your tax return, use the Which? tax calculator to work out your tax bill and submit it directly to HMRC.