National Insurance Number

Your National Insurance number is your unique key for UK tax and National Insurance records. It links your work, taxes, and contributions to the correct account, and it stays with you for life.

Do you need one to start work

You can start work before your number arrives, as long as you can prove your right to work to your employer. Your number helps HMRC and DWP match your records, but it is not itself proof of right to work.

Who can apply

You can apply if you live in the UK, have the right to work, and you are working, looking for work, or have a confirmed job offer.

How to apply, step by step

  1. Create or sign in to your Government Gateway account.

  2. Use the online “Apply for a National Insurance number” service.

  3. Prove your identity online by uploading photos of your passport or other accepted documents.

  4. If you cannot complete identity checks online, you may be asked to post copies or attend an appointment.
    You will receive an email with your application reference and any next steps.

What you will need

  • A valid passport, or

  • A national identity card from an EU country, Norway, Liechtenstein, or Switzerland
    You can still apply without these, you may need to provide alternative evidence or attend an appointment.

If you have lost your number

You can view it in your personal tax account or in the HMRC app after proving your identity. It also appears on payslips, a P60, and some HMRC letters. If you cannot see it online, HMRC can post a confirmation letter to the address they hold for you, or you can use the CA5403 postal form.

National Insurance, how the classes work

There are different classes of National Insurance. The class you pay depends on how you work, how much you earn or profit, and whether you are topping up your record.

Class 1, for employees and employers

  • Employees pay Class 1 through PAYE. In 2025 to 2026, the main rate is 8 percent on earnings between the Primary Threshold and the Upper Earnings Limit, and 2 percent above the Upper Earnings Limit.

  • Employers pay Class 1 at 15 percent on earnings above the Secondary Threshold. Special zero employer rates can apply for eligible employees under 21, qualifying apprentices under 25, qualifying veterans, and some roles in Freeports and Investment Zones, up to set upper secondary thresholds.

  • The key 2025 to 2026 thresholds include the Lower Earnings Limit, Primary Threshold, Secondary Threshold, and Upper Earnings Limit, which are set in weekly and monthly amounts for payroll.

Class 1A and Class 1B, for expenses and benefits

  • Employers pay Class 1A on most taxable benefits in kind, and Class 1B when operating a PAYE Settlement Agreement. The standard rate in 2025 to 2026 is 15 percent.

Class 2 and Class 4, for the self-employed

  • Class 2, a flat weekly amount linked to your profits and State Pension record. In 2025 to 2026, the Small Profits Threshold is £6,845. If your profits are at or above this level, Class 2 is treated as paid for State Pension purposes and you do not pay it in cash. If your profits are below this level, you can pay Class 2 voluntarily to protect your record. The 2025 to 2026 Class 2 rate is £3.50 per week.

  • Class 4 is based on annual profits. In 2025 to 2026, you pay 6 percent on profits between £12,570 and £50,270, and 2 percent above £50,270. Class 4 does not count toward some contributory benefits.

Class 3, voluntary contributions

  • Class 3 is an optional top up if you have gaps in your National Insurance record and want to improve your State Pension position. The Class 3 rate is £17.75 per week in 2025 to 2026. You usually pay the current rate when topping up years outside the special backdating rules.

Paying and checking your record

  • Employees and employers pay through payroll.

  • Most self-employed people pay Class 2 and Class 4 through Self Assessment.

  • You can check your contribution history and any gaps in your personal tax account or the HMRC app, and you can set up voluntary payments if appropriate.

How PK Financial Services can help

  • Guidance with the NI number application and identity checks

  • Help recovering a lost number quickly and correctly

  • Payroll set up for staff and directors, including the correct NI categories and thresholds

  • Self-employed NI planning, Class 2 and Class 4 through Self Assessment, and advice on whether Class 3 voluntary top ups are right for you

Talk to us
PK Financial Services, 49 West Ham Lane, Stratford, London, E15 4PH
T: 0208 22 111 65, 077 897 581 77