If you earn money outside your main employment — from freelancing, a second job, selling items, renting out property or any other activity — this income is likely to be taxable. Understanding the basics helps you stay compliant and avoid surprises.
The £1,000 trading allowance
HMRC provides a £1,000 trading allowance per tax year. If your total income from self-employment, freelancing or selling (not including property income) is below £1,000, you do not need to pay tax on it or report it. If your income exceeds £1,000, you must register as self-employed and declare it.
The £1,000 property allowance
Separately, there is a £1,000 property income allowance for income from renting out property or a room (where the Rent a Room scheme does not apply). Income below this threshold does not need to be declared.
Self Assessment and registration
If your side income exceeds the relevant allowance, you must register for Self Assessment with HMRC, file an annual tax return (usually by 31 January following the end of the tax year), and pay any tax owed. Registration is done via GOV.UK and is free.
What you can deduct
If you are self-employed, you can deduct legitimate business expenses from your income before calculating tax. This includes things like: equipment you use for work, software subscriptions, professional memberships, business travel, and a proportion of your home if you work from home. Personal expenses cannot be deducted.
Selling personal items
Selling your own possessions — clothes, books, furniture — is generally not taxable. However, if you buy items specifically to resell at a profit on a regular basis, HMRC may treat this as trading income. The line between occasional selling and trading can be blurry — if in doubt, check HMRC guidance or speak to an accountant.
Setting aside money for tax
A common mistake for new self-employed people is spending all their side income without setting aside enough for tax. As a rough guide, setting aside 20-25% of your net income for tax is a sensible starting point — though your actual tax rate depends on your total income.