Self Assessment Tax Returns: Complete Guide for the 2024-25 Tax Year

By Surrey Accountants Team — 2025-12-22 — Tax Guides

Understanding Self Assessment

Self assessment is HMRC's system for collecting Income Tax. If you're self-employed, a company director, a landlord, or have other untaxed income, you'll need to complete a self assessment return.

Who Needs to File?

- You're self-employed as a sole trader and earned more than £1,000 - You're a partner in a business partnership - You're a company director - You had untaxed income over £2,500 - You earned over £150,000 in total income - You received income from property letting

The Self Assessment Forms Explained

SA100: The Main Return

Everyone completes the SA100, covering personal details, employment income, interest and dividends, and pension contributions.

SA103S and SA103F: Self Employment