If HMRC writes to you about a compliance check, read what it is asking for and when you need to reply. A calculator cannot decide whether a return is correct or predict a check.
Checked . Based on official GOV.UK guidance. About our calculators and content.
Read the notice carefully
Check the tax, period, records requested and deadline. If the message is unexpected, verify the contact details through HMRC’s official website.
Keep copies of your records
Gather the records HMRC has asked for and keep copies of what you send. Consider an adviser if you dispute a calculation or have complex tax affairs. Do not send documents or HMRC login details to this website.
Source: Read the original rules and guidance. Content checked 23 October 2026. General explanation, not personalised tax advice.