Side hustle tax is the tax you may owe on money you make outside your main job, and the good news is that the first £1,000 is usually tax free under a rule called the trading allowance. Plenty of people spend the summer selling on Vinted, running a market stall, or picking up freelance work, and most never cross the line where HMRC needs to hear from them. The trouble is that the line is easy to miss, and telling HMRC late can mean penalties. Here is exactly when a summer side hustle stays a hobby, and when it becomes something you need to declare.

What the £1,000 trading allowance actually means

The trading allowance lets you earn up to £1,000 a year from self employment or casual trading without paying any tax on it and without having to register for Self Assessment. It covers the total income, not the profit, so it is measured on what comes in before you take off any costs. The GOV.UK guidance on the trading allowance confirms that if your gross trading income for the tax year is £1,000 or less, you generally have nothing to report at all.

It is worth being clear about the difference between a hobby and a trade, because it decides whether the allowance is even in play. Selling a few unwanted personal items you already owned, like clothes from your wardrobe, is not trading and is not taxable, however much you make. Buying or making things specifically to sell them at a profit, or offering a service for payment, is trading, and that is the income the £1,000 allowance applies to. Keeping a simple note of what you sell and what it cost you is the habit our bookkeeping team in Widnes helps side hustlers build so the position is always clear.

When you need to tell HMRC about a side hustle

The moment your gross trading income for a tax year goes above £1,000, you need to register for Self Assessment with HMRC and report it, even if your actual profit after costs is small. Registration is not the same as paying tax, and doing it on time keeps you on the right side of the rules. The steps below walk through what happens as a summer earner grows.

1Under £1,000 gross

If your total trading income for the year is £1,000 or less, the trading allowance covers it. There is nothing to declare and no need to register, though keeping a record is still sensible.

2Over £1,000 gross

Once you pass £1,000 you must register for Self Assessment and complete a tax return. You can choose to deduct the £1,000 allowance instead of your actual expenses if that works out better for you.

3Register by 5 October

You must register by 5 October following the end of the tax year in which you crossed the limit. So income earned in the 2026 to 2027 tax year means registering by 5 October 2027.

4File and pay by 31 January

The online tax return and any tax due are then payable by 31 January. Register early so your Unique Taxpayer Reference arrives in good time and the deadline never catches you out.

A quick example shows how it works in practice. Say you make handmade candles and take £1,400 over the summer, with £500 of costs for wax and jars. Your gross income is above £1,000, so you must register and report. You then choose the better of two options: deduct your real £500 of costs and pay tax on £900 of profit, or deduct the flat £1,000 allowance and pay tax on £400. Here the flat allowance wins, which is exactly the kind of choice our taxation team runs through with clients so nothing is left on the table.

The online platform reporting rules explained

You may have heard that selling apps now pass information to HMRC, and that has understandably made a lot of casual sellers nervous. Under rules that took effect from January 2024, digital platforms report seller details to HMRC where a seller makes around 30 sales or roughly £1,700 in a year. This is a reporting threshold, not a new tax, and it does not change the £1,000 trading allowance one bit. If you are genuinely just clearing out your own belongings, you still owe nothing, but you may want a tidy record in case HMRC asks a question.

The sensible takeaway is that being visible to HMRC and owing tax are two different things. Someone selling off an old wardrobe could trip the platform report without owing a penny, while a small maker below it might still need to declare. If you are unsure which side of the line you sit on, our business support team can look at your situation and tell you plainly where you stand.

Common side hustle tax mistakes to avoid

None of these are hard to avoid once you know the rules, and a short conversation early on usually saves a scramble later. A tidy record of what you sold, and what it cost you, makes any tax return quick and stress free. It is one of the simple habits we help owners build alongside their summer cash flow planning so the money side never becomes a worry.

Frequently Asked Questions

Earn with confidence this summer

A summer side hustle should be about the extra income and the enjoyment, not a nagging worry about tax. Know the £1,000 line, keep a tidy record, and register in good time if you go over. If you would like someone to check where you stand or take the tax return off your hands, get in touch with FD Accountants for a free initial consultation with no obligation.