If you’re wondering ‘do I need to complete a tax return?’ you’re not alone. A Self-Assessment tax return is how some people report their income to HMRC and pay any tax they owe. If you’re self-employed, earn extra income outside your job or meet certain other criteria, you may need to file one. Understanding your responsibilities is key to avoiding penalties and keeping on top of your finances.

What is a tax return?

A tax return is a form used to declare your income and expenses to HMRC. For most people, tax is deducted automatically from their wages or pension, but if you earn money that isn’t taxed at source, you might need to file a tax return to calculate what you owe.

It covers all your income sources, deductions and any tax reliefs you may be eligible for. Once submitted, HMRC will determine how much you owe or whether you’re owed a tax refund.

Who needs to complete a tax return?

Not everyone has to submit a tax return, but you’ll need to if any of the following apply to you:

Self-employed

If you’re a sole trader and have earned more than £1000 in the tax year, you must register for Self-Assessment and file a tax return. Even if you didn’t make much profit, HMRC still requires you to report your earnings.

Landlords

Earning rental income? You need to report it, even if you don’t make a profit. This includes renting out property, holiday lets or rooms under the Rent a Room Scheme. Even if you’re just renting out part of your home, you may still have tax obligations.

Rental income tax calculator

High earners

If your income exceeds £100,000, HMRC requires you to file a tax return – even if you’re employed and already paying tax through PAYE (Pay As You Earn). This is because tax-free allowances reduce as income increases, meaning you might owe more tax than what’s already deducted from your salary.

Those with additional untaxed income

Received dividends, foreign income or money from investments? You may need to file a tax return to make sure you’re paying the correct tax. Even income from side hustles, freelancing or selling online could mean you need to declare earnings to HMRC.

What happens if you don’t file?

Ignoring your HMRC tax return obligations can be costly. If you miss the deadline you could face:

  • Late filing penalties: A £100 fine if you’re even a day late, with additional charges if you continue to delay. After three months, daily penalties of £10 per day can apply, up to £900.
  • Interest on late payments: The longer you take, the more you’ll owe in interest and fines. HMRC applies interest on unpaid tax from the day after the deadline.
  • Further HMRC action: Persistent non-compliance can lead to investigations and legal consequences. In serious cases, HMRC can seize assets or take legal action against those who avoid filing.

How to file a tax return

Filing a tax return doesn’t have to be stressful. Here’s how it works:

  • Online vs paper: Filing online is quicker and gives you extra time compared to the paper deadline. HMRC’s online system also provides automatic calculations and prompts to help you avoid errors.
  • Deadlines: Paper returns must be in by 31st October, while online submissions are due by 31st January. If you’re registering for Self-Assessment for the first time, you must do so by the 31st of October.

Key tax dates & deadlines

Tips for filing on time

  • Get your documents ready: Gather your P60, invoices, expense records and any other relevant paperwork.
  • Use HMRC’s system or an accountant: If your return is straightforward, you can file it yourself. If not, a tax expert can help ensure accuracy and maximise your deductions.

Stay on top of your taxes with RIFT

Filing a tax return doesn’t have to be complicated. Whether you’re self-employed, a landlord or earning extra income, staying compliant with HMRC is essential. If you’re still confused as to who needs to file a tax return, or just want to make sure you’re claiming the right reliefs, RIFT is here to help. Check out our tax calculators to help you work things out.