How to Complete a Self-Assessment Tax Return – Top 10 Tips

If you’re a UK taxpayer required to submit a self-assessment tax return, you’re not alone. Many individuals, from self-employed professionals to landlords, find the process daunting. At Accounting Wise, we aim to simplify the process for you. This guide will show you how to do a self-assessment tax return correctly and efficiently.

What Is a Self-Assessment Tax Return?

A self-assessment tax return is how HMRC collects income tax from those who do not have it automatically deducted. If you’re self-employed, a landlord, or earning income from savings or dividends exceeding certain thresholds, you’ll likely need to submit one.

The deadline for online submission is 31 January following the end of the tax year (5 April). Missing this deadline can result in penalties, so preparation is key.

Top 10 Tips for Completing Your Self-Assessment Tax Return

1. Know If You Need to File
   Before diving into the process, confirm if you need to file a tax return. Common reasons include:
   • you were self-employed as a ‘sole trader’ and earned more than £1,000 (before taking off anything you can claim tax relief on)
   • you were a partner in a business partnership
   • you had a total taxable income of more than £150,000
   • you had to pay Capital Gains Tax when you sold or ‘disposed of’ something that increased in value
   • you had to pay the High Income Child Benefit Charge
2. Register with HMRC
   If it’s your first time, register for self-assessment on the HMRC website. Allow up to 10 working days for your Unique Taxpayer Reference (UTR) to arrive, as it’s essential for completing the form.
3. Organise Your Records
   Keep records of all income, expenses, and deductions. Essential documents include:
   • Payslips and P60s
   • Invoices and receipts
   • Bank statements
   • Any correspondence with HMRC
4. Understand Taxable Income
   Your taxable income includes earnings from employment, self-employment, rental income, savings, dividends, and foreign income. Knowing what to include prevents under-reporting.
5. Claim Allowable Expenses
   If you’re self-employed, you can reduce your taxable income by claiming allowable business expenses. These may include office supplies, travel costs, and even a portion of your home bills if you work from home.
6. Utilise Tax Reliefs
   Make the most of tax reliefs available to you, such as pension contributions, charity donations under Gift Aid, or certain investment schemes.
7. Double-Check Your Details
   Ensure all personal details, such as your UTR, National Insurance number, and bank information, are correct. Mistakes can lead to delays or penalties.
8. Use HMRC’s Online Services
   Filing online is quicker and easier. HMRC’s online portal offers step-by-step guidance, and the system automatically calculates your tax liability.
9. Submit Early
   Don’t wait until the deadline. Submitting your tax return early gives you time to rectify errors, understand your tax bill, and plan for payments.
10. Seek Professional Help
    If you’re unsure how to complete a self-assessment tax return, a professional accountant can save you time, stress, and money. Accounting Wise specialises in assisting individuals and businesses with accurate and timely filings.