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How to Claim a Refund of Class 1 National Insurance
If you've overpaid Class 1 National Insurance contributions as an employee, you may be entitled to a refund. This typically happens when you've worked multiple jobs in the same tax year or your employer has deducted too much. HMRC will write to you if they identify an overpaym...
Introduction
If you've overpaid Class 1 National Insurance contributions as an employee, you may be entitled to a refund. This typically happens when you've worked multiple jobs in the same tax year or your employer has deducted too much. HMRC will write to you if they identify an overpayment, and you can then claim your money back.
What are Class 1 National Insurance contributions?
Class 1 National Insurance contributions (NICs) are payments deducted automatically from your wages if you're an employee. Your employer takes these from your pay before you receive it, alongside income tax. They're separate from Class 2 and Class 4 contributions, which self-employed people pay.
When you might be owed a refund
You may have overpaid Class 1 National Insurance in several situations:
Working two or more jobs at the same time — Each employer deducts National Insurance separately based on your earnings with them. They don't know what you earn elsewhere. If your combined earnings from all jobs push you over certain thresholds, you can end up paying more than necessary.
Your employer deducted too much — Sometimes errors in payroll systems mean too much National Insurance is taken from your wages during the year.
You stopped working partway through the year — The way National Insurance is calculated week-by-week or month-by-month can sometimes result in overpayments if your employment pattern changes.
How HMRC identifies overpayments
HMRC reviews National Insurance records after the end of each tax year. If their system identifies that you've overpaid, they'll send you a letter explaining the overpayment and inviting you to claim a refund.
You should not apply for a refund unless you've received this letter from HMRC. The letter confirms that HMRC has reviewed your records and calculated that you're owed money.
How to claim your refund
Wait for HMRC to contact you
The most important rule is to wait for HMRC to write to you before claiming. If you believe you've overpaid but haven't received a letter, HMRC needs to complete their review first.
Apply online
Once you've received your letter from HMRC, you can apply for your refund online. You'll need to sign in to HMRC's online service. If you don't already have login details (a Government Gateway account), you can create them when you start the application.
Information you'll need
When you apply, have the following ready:
- The letter from HMRC about your refund
- The names of all employers you worked for during the tax year the refund relates to
- Your National Insurance number
- Details of your bank account where you want the refund paid
Applying by post
If you prefer not to apply online, you can use the postal form that HMRC sent with your letter. Complete this and return it to the address shown.
What happens after you apply
After you submit your claim, HMRC will process your refund. You can check their current processing times to see when you can expect a reply.
The refund will be paid directly into the bank account you provided. Make sure the account details you give are correct to avoid delays.
If you haven't received a letter
If you believe you've overpaid Class 1 National Insurance but haven't received a letter from HMRC, don't apply using the process described above. That system is specifically for people who have already been contacted.
HMRC's systems review National Insurance records automatically after each tax year ends. If there's a genuine overpayment, they should identify it. However, if you're concerned, you can:
- Check your payslips to see what's been deducted
- Contact HMRC directly to query your National Insurance record
- Speak to your accountant to review whether an overpayment has occurred
Understanding the tax year
National Insurance, like income tax, operates on a tax year basis. The 2025/26 tax year runs from 6 April 2025 to 5 April 2026. HMRC typically reviews overpayments and sends letters in the months after a tax year ends, so you might receive a letter about 2024/25 overpayments during summer or autumn 2025.
Important points to remember
- Only apply if you've received a letter from HMRC inviting you to claim
- Keep the letter from HMRC safe as you'll need information from it
- Online applications are usually faster than postal ones
- Make sure you have details of all employers from the relevant tax year
- Double-check your bank details before submitting your claim
- Don't confuse Class 1 refunds with other types of National Insurance — this process is specifically for employees
Sources
This article provides general guidance based on current HMRC rules. For advice specific to your situation, speak to your accountant.
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