HMRC introduced a new digital process for claiming overpaid NIC in specific circumstances in April 2026. The process is open to individuals who have received a letter from HMRC informing them that they may be due a refund. The letter includes a claim reference number, which needs to be inputted when making the claim.

Only individuals who may have had class 1 NIC overpaid in error by their employer will receive a letter. The letter will also include details of class 2 and 3 NIC as well as national insurance credits. Individuals are encouraged to check if this information is accurate. However, the digital process for claiming a refund claim is for overpaid class 1 NIC only.  

If the individual believes that an error has been made, there is an opportunity to correct this during the process. Individuals who cannot claim a refund online can use the form at the back of the letter. The online service cannot be used by a personal representative or employer. 

Once HMRC has received the application, it will check the application and write to the individual with the outcome. Indicative reply times from HMRC’s Where’s my reply tool indicate that the individual may receive a quicker response if they use the new digital process.  

HMRC has also published an online tool that can help individuals check how to claim a NIC refund. This may be of use where the individual:  

• believes they have overpaid class 1 NIC but has not received a letter with a claim reference; or 
• thinks they may have overpaid a different class of NIC.