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HMRC Error: Class 2 National Insurance Contributions and What It Means for You

Woman pondering tax bill
  • August 19, 2025
Dean Shepherd

If you’re self-employed and recently filed your Self Assessment, you may have noticed something strange on your tax calculation. HMRC has confirmed there’s been a glitch with how Class 2 National Insurance Contributions (NICs) have been applied  — and it’s left some people with the wrong bill.

 

What’s happened?

In some cases, HMRC’s system has incorrectly added a Class 2 NICs charge of £358.80 (or less, depending on circumstances) to taxpayers’ accounts. This has mostly affected those with self-employed profits over £12,570 — people who shouldn’t have had the charge added at all.

 

What is HMRC doing about it?

HMRC is:

  • Automatically correcting some records where they have the right information. If this applies to you, you’ll have received a message letting you know.
  • Working through remaining cases and issuing corrected tax calculations (SA302s) once fixed. These will come with a new 30-day deadline to pay.
  • Continuing to send letters with incorrect NIC figures until their IT issue is fixed (expected September). This means you may still receive a confusing letter even if your record is correct.

If you’ve already made a payment, HMRC says you’ll either be refunded or receive a credit against your Self Assessment account.

 

What should you do?

  • Don’t panic – HMRC has confirmed this won’t have a long-term impact.
  • Check your SA302 (tax calculation) carefully – if the NICs figure doesn’t look right, you’re not alone.
  • Wait for HMRC’s correction – they’ll issue a new SA302 once your record is fixed.
  • Speak to your accountant if you’re unsure whether the amount showing on your statement is correct.

The bottom line

This is one of those frustrating HMRC IT hiccups that causes worry in the short term, but it should all come out in the wash. The key thing is:

  • No one should end up overpaying NICs permanently.
  • HMRC is aware and fixing the problem.
  • Refunds or credits will be issued where needed.

If you’re self-employed and concerned about whether you’ve been affected, check in with your accountant (or drop us a message) — we can help you make sense of your tax calculation and make sure everything is in order.



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