Top Three Tips to File Your Self-Assessment Correctly and Avoid Penalties

Self-employed professionals, landlords, high-income employees or those who generate income in addition to PAYE may be required to compete a self-assessment tax return.

If this is you, whilst it can feel like a looming administrative burden it’s actually an opportunity to get clarity on your finances, optimise your tax position, and demonstrate strong financial control. The key is to do it correctly and early, so you avoid unnecessary penalties.

With the right approach, you can stay compliant, avoid penalties and even improve your financial position. Here are the top three essential tips to achieve that:

1. Start Early

Most penalties come from late filing. Get ahead by organising receipts, tracking income monthly and collecting key documents as soon as they’re available. Early prep gives you time to fix errors and spot tax-saving opportunities.

2. Know What You Can Claim

Accuracy is everything. Double-check all income streams and understand which expenses are genuinely allowable. Avoid common errors like mixing personal and business costs or forgetting pension contributions that could reduce your personal tax liability.

3. Use Professional Support

HMRC rules change often. A specialist finance company can help you optimise reliefs, avoid mistakes and navigate complexity, saving you stress and potential fines.

For the 2024/25 tax year – running 6 April 2024 to 5 April 2025 – here are some important deadlines:

• Register for Self-Assessment by 5 October 2025 if you’ve never submitted a return before

If you missed the 5 October 2025 deadline, you should register immediately to minimise potential penalties

• Submit your return by midnight 31 October 2025 if filing a paper tax return
• Submit your return by midnight 31 January 2026 if filing online
• Pay the tax you owe by midnight 31 January 2026

Filing correctly isn’t just about compliance, it’s smart financial leadership. If you’re looking for expert guidance with your Self-Assessment, RollPay can help – let us identify allowable expenses and reliefs, and prepare and submit your return for you.

Contact RollPay for more information.