HMRC confirms issue with CJRS calculator

08 February 2021

HMRC has confirmed that, unfortunately, the Coronavirus Job Retention Scheme (CJRS) calculator contained a software error, but that this has now been rectified.

What this does mean, however, is that anybody who utilised the calculator prior to 21 January 2021 to calculate January 2021 claims for employees who are not on a fixed salary will be required to re-calculate their claims if:

  • They used an employee’s pay for January 2019 as reference pay, instead of 2020, and
  • Their pay was different in January 2019 to January 2020

Where January 2020 pay was used, there is no need for claimants to take any further action.

HMRC has apologised to anybody who will now be required to re-calculate their claims.

If, upon performing the re-calculation, it is apparent that the claim amount was incorrect, then:

  • If a claim for too much has been submitted, this should be amended in the next CJRS claim submission. Alternatively, HMRC should be notified as soon as possible, and a repayment made either online, through HMRC’s card payment service or by bank transfer – further guidance on this is available here
  • If a claim for too little was submitted, then claimants should call the helpline to get this corrected by 1 March 2021


The information in this article is accurate at the time of publication. For all the latest information, news and resources on how the COVID-19 pandemic is affecting payroll professions, visit our Coronavirus hub.