Self Assessment Tax Returns

A Self Assessment tax return is how you report your income to HMRC if you’re self-employed or have income that isn’t taxed at source. The system requires you to calculate your own tax liability, hence the name “Self Assessment.”

You’ll need to file a Self Assessment if:

• You’re self-employed or a sole trader
• You’re a partner in a business partnership
• You’ve received untaxed income, such as from property rentals
• You have capital gains to report
• You need to claim tax relief or expenses
• You have foreign income to declare

Key Deadlines for 2025/26 Tax Year

For the current tax year:

• Paper returns: 31 October 2025
• Online returns: 31 January 2026
• Tax payment: 31 January 2026

Missing these deadlines can result in penalties starting at £100 and increasing the longer you delay.

How to Register for Self Assessment

If you’ve never completed a Self Assessment before, you’ll need to register with HMRC:

1. Visit GOV.UK and search for “register for Self Assessment”
2. Create your Government Gateway account
3. Wait for your Unique Taxpayer Reference (UTR) to arrive by post (usually within 10 working days)
4. Activate your account using the code provided

Filing Your Self Assessment Online

HMRC’s online service makes completing your tax return straightforward:

1. Log in to your personal tax account at GOV.UK
2. Select “Complete Self Assessment tax return”
3. Follow the step-by-step instructions to enter your income and expenses
4. Review your information before submitting
5. Pay any tax due by the deadline

Getting Help with Your Self Assessment

If you’re struggling with your tax return, several options are available:

HMRC Support

• HMRC’s Self Assessment helpline: 0300 200 3310
• Online guides and webinars at GOV.UK
• Virtual assistant service on the HMRC website

Professional Help

Consider hiring an accountant if:

• You’re newly self-employed and unfamiliar with the process
• Your financial affairs are complex
• You want to ensure maximum tax efficiency
• You lack time to complete the return yourself

Common Self Assessment Mistakes to Avoid

1. Missing deadlines – set calendar reminders
2. Forgetting to include all income sources
3. Not claiming eligible expenses and reliefs
4. Errors in calculations
5. Failing to keep adequate records

Record Keeping for Self Assessment

Good record keeping is essential for accurate tax returns. Keep records of:

• All business income and expenses
• Bank statements and invoices
• Receipts for business expenses
• Previous tax returns and calculations
• Details of other personal income

Records should be kept for at least 5 years after the submission deadline.

Self Assessment for Different Tax Situations

Self-Employed Individuals

As a self-employed person, you’ll need to record all your business income and expenses. You can choose between cash basis or traditional accounting depending on your business size.

Landlords and Property Income

If you receive rental income, you must declare this on your Self Assessment. Various expenses related to property management can be deducted.

Capital Gains

If you’ve sold assets at a profit, such as shares or a second property, you’ll need to calculate and report your capital gains.

PAYE Employees with Additional Income

If you’re employed but also have additional income that exceeds certain thresholds, you’ll need to complete a Self Assessment.

Need Further Assistance?

At Tax Return Assist, we specialize in making Self Assessment simple. Our team of tax experts can help with every aspect of your tax return, from registration to submission and beyond.

Contact us today for professional, reliable help with your Self Assessment tax return and ensure you remain compliant with HMRC requirements while maximizing your allowable deductions.