The Side Hustle Tax Trap

What Counts as Income

If you sell on Vinted, post on TikTok or Instagram for brands, or freelance on the side of a full-time job, HMRC now has a much clearer picture of what you're earning than it used to. Since January 2024, platforms including eBay, Vinted, Etsy and Airbnb have been required to report seller data straight to HMRC. That doesn't mean there's a new tax on side hustles. It means the numbers you might once have quietly kept off your tax return are now sitting on HMRC's desk anyway.

The £1,000 trading allowance

Everyone gets a £1,000 tax-free trading allowance each tax year. It covers all your side income together, not £1,000 per platform or per activity. Sell £600 of clothes on Vinted and earn £500 from freelance writing in the same tax year, and you're over the threshold even though neither activity alone would trip it.

Cross £1,000 in gross income and you need to register for Self Assessment and file a return. Gross means before any costs, so postage, platform fees, and materials don't reduce the figure that decides whether you're in scope.

Content creators: it's not just cash that counts

This is the part that catches people out. If a brand sends you free products in exchange for posting about them, that's income, valued at what the product is worth, not what changed hands as cash. HMRC's own example makes the point well: £700 in paid fees, plus £300 of gifted goods, plus £200 of ad revenue, adds up to £1,200. That's over the threshold even though only £900 actually landed in a bank account.

So if you're a creator tallying up whether you need to register, the gifted hauls and sponsored freebies need to go in the total alongside anything you were actually paid.

Why platforms are reporting you now

The reporting rules aren't aimed at catching people out retrospectively. They exist so HMRC can cross-check what platforms say you earned against what you declare. Platforms report sellers who make more than around 30 sales or over £1,700 in a year, and they're required to give you a copy of what they've sent. If those numbers don't match your tax return, or you haven't filed one at all, that's now a much easier gap for HMRC to spot than it was a few years ago.

The deadline that matters

If you crossed £1,000 in gross side income during the 2025/26 tax year (6 April 2025 to 5 April 2026), you need to register for Self Assessment by 5 October 2026. Miss it and HMRC can charge a failure-to-notify penalty, worked out as a percentage of any tax you owed late. It can run from 0% up to 30% for a non-deliberate failure, more for anything deliberate. If you register late but still pay everything owed by the usual 31 January deadline, the penalty is often reduced to nil, but that's not guaranteed and it's not a reason to leave registration until the last minute.

One thing to flag, carefully

The government has said it wants to raise the trading allowance from £1,000 to £3,000, with a simpler digital process for people below the new line who still owe something. As things stand, this hasn't been legislated. Until it is, the £1,000 threshold is what applies, so don't let talk of a future change stop you registering now if you're already over the current line.

What to do if this is you

•       Add up everything you've earned from side activities in 2025/26, cash and gifted products together, across every platform.

•       If the total is over £1,000 gross, register for Self Assessment before 5 October 2026.

•       Download your transaction history from each platform now, before you need to reconstruct a year of sales from memory.

•       Keep gifted products and their approximate value on record separately, since they're easy to forget when you're adding things up later.

•       If you're not sure whether you're over the line, or you want it checked properly before you register, get in touch with the team at Highwoods Group and we'll go through it with you.

The bottom line

This isn't really a new rule, it's an old rule that's suddenly much harder to miss. Platforms are already telling HMRC what you've earned, so the safest move is to know your own numbers before HMRC asks about them.

Highwoods Group helps sole traders, landlords and growing SMEs stay ahead of their tax obligations. If you're unsure whether your side income needs declaring, get in touch and we'll walk through it with you.

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