• What is Self-Assessment?

Self-assessment is HMRC's system for collecting income tax from individuals whose tax isn't automatically deducted through PAYE. If you're self-employed, earn rental income, have investment income over £10,000, or receive untaxed income above £1,000, you must file a self-assessment tax return annually.

The tax return calculates your total income from all sources, deducts allowable expenses and reliefs, then works out how much tax you owe. The deadline is 31 January following the tax year end (5 April), with late filing resulting in automatic £100 penalties plus daily charges if delays continue.

• Who needs to file a personal tax return?

You must file a self-assessment tax return if you:

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• Are self-employed as a sole trader with income over £1,000

• Are a company director (unless paid only through PAYE)

• Earn rental income from property over £1,000 (before expenses)

• Have untaxed income over £1,000 from other sources

• Receive dividend income over £10,000

• Have capital gains above the annual exemption (£3,000 for 2024/25)

• Earn over £100,000 annually (to repay child benefit or adjust personal allowance)

• Have foreign income or assets requiring declaration

• Are a trustee, partner in a business partnership, or religious minister

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​You must register with HMRC by 5 October following the tax year end, even if you have no tax to pay. For the 2025/26 tax year (ending 5 April 2026), registration must be completed by 5 October 2026 and the return filed by 31 January 2027.

• What is a personal tax allowance?

The personal tax allowance is the amount you can earn before paying income tax - currently £12,570 for 2025/26. You pay no tax on income up to this amount. Income above £12,570 is taxed at 20% (basic rate), 40% (higher rate) or 45% (additional rate) depending on total earnings. Some people qualify for additional allowances like Marriage Allowance or Blind Person's Allowance.

• Can I do my own tax return?

Yes, you can complete your own return using HMRC's online system or commercial software. However, professional services typically save more in additional tax deductions than the fee costs, while avoiding errors that trigger penalties and investigations. If your tax affairs involve self-employment, rental income, capital gains or multiple income sources, professional preparation delivers significant value.