HMRC Self-Assessment is the main way for millions of UK taxpayers to report their income and figure out how much tax they owe. It allows individuals to manage their own tax matters while following UK tax laws.
Understanding self-assessment is important for:
Self-employed professionals
Business partners
Landlords with rental income
High-income earners
Those with significant investment returns
At TaxCan, we help you through every step of the self-assessment process, making it easy and stress-free to comply with tax regulations.
This guide covers:
What documents you need to file
Important deadlines you must meet
When and how to make tax payments
How to avoid penalties for late filing or payment
Any recent changes in tax laws that may affect you
Where to find additional support or resources
Whether you’re filing your self-assessment for the first time or looking for ways to improve your tax reporting, this article has all the information you need to navigate HMRC Self-Assessment confidently.
Who Needs to File a Self-Assessment Tax Return?
HMRC requires specific categories of taxpayers to submit a Self-Assessment tax return. Here’s a comprehensive breakdown of who needs to file:
Self-Employed Individuals
Sole traders earning more than £1,000
Partners in business partnerships
Freelancers and contractors
Property Income
Landlords with rental income
Holiday let owners
Those earning from overseas property
Additional Income Sources
Dividend payments exceeding £10,000
Interest from savings above £10,000
Foreign income subject to UK taxation
Special Circumstances
Directors of limited companies
Ministers of religion
Trustees or representatives of someone deceased
The requirement to file extends to individuals who:
Earned over £100,000 in the tax year
Need to claim tax relief on pension contributions
Received Child Benefit while earning over £50,000
Made profits from selling assets subject to Capital Gains Tax
HMRC provides an online checking tool to determine your filing requirements. This tool asks specific questions about your income sources and circumstances to confirm whether you need to complete a Self-Assessment tax return.
Check if you need to file a Self-Assessment
Key Deadlines for Filing
Meeting HMRC’s submission deadlines is crucial to avoid penalties and maintain compliance with tax regulations. Here are the key dates you need to mark in your calendar:
Paper Returns
Deadline: 31 October following the tax year
Submission: Returns must reach HMRC by midnight
Preparation: Allow sufficient time for postal delivery
Online Returns
Deadline: 31 January following the tax year
Access: System accessible 24/7 until midnight of the deadline
Confirmation: Immediate confirmation of submission provided
First-Time Filers
Registration deadline: 5 October following the tax year
UTR receipt: Allow 20 working days to receive your Unique Taxpayer Reference (UTR)
Activation code receipt: Additional 10 working days to receive activation code for online services
Important Tax Year Dates
Tax year runs: 6 April to 5 April
Registration period opens: 6 April
Paper returns window: 6 April – 31 October
Online submission window: 6 April – 31 January
Missing these deadlines can result in automatic penalties, starting at £100 and increasing over time. Setting up reminders and preparing documentation well in advance helps ensure timely submission.
Read our guide on managing tax deadlines effectively
Payment Obligations and Penalties
Understanding your tax payment schedule and potential penalties helps you maintain compliance and avoid unnecessary charges.
Key Payment Dates:
January 31st – Final payment for the previous tax year and first payment on account
July 31st – Second payment on account
Payment on Account Structure:
Each payment equals 50% of your previous year’s tax bill
Applies when your tax bill exceeds £1,000
Exceptions exist for those with 80% of tax deducted at source
Late Payment Penalties:
Initial Penalty5% of tax unpaid after 30 days
Additional 5% after 6 months
Further 5% after 12 months
Interest ChargesHMRC applies interest on late payments
Current rate: 7.75% per annum
Penalty Appeals
HMRC considers appeals for penalties under reasonable excuses:
Serious illness
System failures
Natural disasters
Bereavement
Tip: Set up a Direct Debit for automatic payments to avoid missing deadlines
HMRC offers Time to Pay arrangements for those struggling to meet payment deadlines. Contact them before the due date to discuss payment plans and potentially avoid penalties.
Learn more about tax payment arrangements
Filling Out the Tax Return
The SA100 form is your main self-assessment tax return document. This comprehensive form captures essential information about your income, expenses, and tax obligations for the relevant tax year.
Key Sections of the SA100:
Personal details and UTR number
Income from employment
Self-employment earnings
Property income
Investment returns
Pension contributions
Student loan repayments
HMRC provides detailed guidance notes for each section of the SA100 form. These notes explain:
Required documentation
Eligible expenses
Calculation methods
Common errors to avoid
Essential Record Keeping:
Keep receipts and invoices for 6 years
Document business expenses systematically
Track mileage and travel costs
Save bank statements and financial records
Store digital copies of important documents
Pro Tip: Use HMRC’s online portal to complete your SA100. The system includes built-in calculators and automatic validation checks to help prevent errors.
Need help organizing your tax records? Learn about our bookkeeping services
Updates and Changes in Regulations
Tax regulations evolve each year, reflecting economic changes and government policies. The 2023/24 tax year introduced significant modifications:
New Tax Thresholds
Personal Allowance frozen at £12,570
Higher rate threshold maintained at £50,270
Additional rate threshold reduced to £125,140
Digital Requirements
Making Tax Digital (MTD) expansion for self-employed individuals
Mandatory digital record-keeping from April 2024
Compatible software requirements for submissions
HMRC communicates updates through multiple channels:
Direct emails to registered users
Official HMRC website announcements
Annual budget statements
Tax bulletins and newsletters
Staying Updated
Subscribe to HMRC email alerts
Check the official HMRC website monthly
Follow HMRC social media accounts
Review guidance notes before each filing period
Key Resources
HMRC’s YouTube channel for visual guides
Self Assessment helpsheets
Interactive webinars
Online customer forums
These changes impact filing methods, allowable expenses, and reporting requirements. Professional guidance through TaxCan’s services helps navigate complex regulatory updates while ensuring compliance with current legislation.
Resources for Assistance
HMRC provides multiple support channels to help you navigate your self-assessment journey:
HMRC Self Assessment Helpline: 0300 200 3310 (8am to 6pm, Monday to Friday)
Online Webchat Service: Available through your Government Gateway account
Self Assessment YouTube Tutorials: Step-by-step video guides for filing returns
HMRC Mobile App: Track your tax affairs on the go
TaxCan offers specialized guidance through these valuable resources:
Understanding Tax Returns for Small Businesses
For complex tax situations, consider seeking professional help:
Certified accountants
Tax advisors
Professional tax preparation services
Pro Tip: Save the HMRC helpline number in your contacts and bookmark relevant TaxCan guides for quick access during tax season.
FAQs(Frequently Asked Questions)
A: HMRC Self-Assessment is a system used by HM Revenue and Customs (HMRC) to collect Income Tax from individuals who are self-employed or have other untaxed income. It is important for taxpayers to understand this process as it determines their tax obligations.
A: Individuals who must file a Self-Assessment tax return include those who are self-employed, receive rental income, earn dividends, or have other untaxed income. You can use HMRC’s online tool to determine if you need to file.
A: Key deadlines include submitting paper returns by October 31 and online returns by January 31 of the following year. First-time filers must notify HMRC by October 5.
A: Taxes under Self-Assessment are typically due on January 31 and July 31 each year. Late payments can incur penalties, so it’s crucial to meet these deadlines.
A: The SA100 form is the main document used for filing a Self-Assessment tax return. It’s essential to follow the guidance notes provided by HMRC when filling out this form to ensure accuracy.
A: HMRC offers various resources for assistance with Self-Assessment, including guidance notes, online tools, and support articles. You can also find complementary information on TaxCan.
