HMRC deadline this weekend as millions of people urged to 'check' nowThe cut-off for registering for self-assessment for the 2024/25 tax year is October 5 - see the full list of everyone who needs to take action nowView Image The HMRC self-assessment register deadline is October 5 (Image: GETTY)If you're newly self-employed or earned more than £1,000 in one tax year through a side hustle, then you may need to register for self-assessment with HMRC - and the deadline is this weekend. ‌Once you have registered for self-assessment, HMRC will issue you with a unique taxpayer reference (UTR) number. October 31 is the deadline for filing a paper self-assessment tax return, and January 31 is the deadline for filing your online self-assessment. You'll also be fined £100 for missing the online January 31 deadline. If you still don't file your self-assessment after three months, you'll be charged additional fines of £10 a day, up to a maximum of £900.