What HMRC Considers “Trading” (And Where It Gets Tricky)
HMRC doesn’t care whether you call yourself a “business” or just “doing a bit on the side.” They care about pattern, profit motive, and repetition. If you’ve sold something once, that’s probably just a one-off. Do it again? Start advertising? Reinvest profits into stock or tools? That’s when eyes start turning your way. The technical term is “the badges of trade” – nine factors HMRC uses to sniff out whether an activity is trading or not, like frequency of transactions, the nature of the asset, and how much effort you’re putting in.
Let’s say you bought a vintage amplifier for £200, restored it over weekends, and sold it for £650. Then repeated that twice more. That’s not just clearing clutter. That’s trading. Even if you’re not calling it a business. Even if you’re doing it from your garage. You’re structured, you’re profiting, you’re repeating. And that changes everything. Now imagine doing the same but with handmade soaps. Same principle. Same risk. The thing is, most people don’t think about this enough—they assume turnover under a certain threshold is “safe.” It’s not. Registration isn’t about how much you earn. It’s about whether you’re trading at all.
But—and this is where it gets personal—HMRC aren’t hunting hobbyists. They’re after consistent, profit-driven activity. So if you sold your old guitar on Facebook Marketplace, no, you don’t need to register. But if you’re flipping instruments regularly, sourcing them with intent, upgrading them, taking photos, writing listings—then yes, you’re on the radar. And that’s exactly where many freelancers misstep. They start with one client. Then another. Then a third. Suddenly they’re self-employed. But they never told HMRC. Oops.
How the Three-Month Rule Actually Works (And Why Dates Matter)
The clock starts ticking from the date you first start trading—not when you get paid, not when you register the domain, not when you open a business bank account. The first invoice sent. The first gig completed. The first sale made. That’s day zero. And you have 92 days to register for Self Assessment. No extensions. No “I didn’t know” excuse. The deadline is firm. Register late? You’ll get an automatic £100 penalty. Even if you owe no tax. That’s not a typo: £100. For being late. And if it’s more than 12 months late? Another £300, or 5% of the tax due—whichever is higher.
To give a sense of scale: imagine you started tutoring in January, made £1,200 by April, and didn’t register until October. You’re seven months late. That’s at least £100. Maybe more. And that’s before any interest on unpaid tax. Now multiply that by the 60,000+ people who start side businesses each year without realising this rule exists. The system assumes you know. It doesn’t care if you didn’t get a letter. It doesn’t care if your friend said “wait until you file.” That’s not how it works.
And here’s the kicker: you can register before you start. Yes, really. There’s no rule saying you can’t notify HMRC in advance. In fact, it’s a smart move. Do it in January, start trading in February, and you’re golden. No stress. No ticking clock. You’re ahead of the game. The issue remains—most wait until they’re asked by a client for a VAT number, or until they’re applying for a mortgage and realise they’ve not declared income. By then, you’re already behind.
Registering vs. Filing: What You Actually Need to Do
People mix these up constantly. Registering is telling HMRC “I exist as a trader.” Filing is submitting your tax return each year. You must do both—but at different times. Register early. File by 31 January following the end of the tax year (so for 2023/24, that’s 31 January 2025). But because you’re new, you might not hear from HMRC straight away. They’ll send a letter—eventually—asking you to file. But you don’t wait for that. You act first.
Here’s the process: go online, apply for a Unique Taxpayer Reference (UTR). Takes 15 minutes. Then wait 10 days (sometimes up to 21) for the UTR to arrive. Then register for Self Assessment. Once that’s done, HMRC will confirm. You’re in the system. You can start trading legally. But—and this is critical—you now have obligations: keep records, track income and expenses, report accurately. It’s a bit like getting a driver’s license. The hard part isn’t passing the test. It’s remembering to renew it and follow the rules every day after.
And that’s where small business owners fall down. They think registering is the finish line. It’s not. It’s the starting gun. Because now you’re on the hook for two tax payments a year: one in January, one in July. You might need to pay Class 2 and Class 4 National Insurance. You might need to consider VAT if you hit £90,000 in turnover. None of this is optional. And honestly, it is unclear how many new traders actually grasp the full scope. Data is still lacking, but anecdotal evidence suggests over half are unaware of payment on account rules.
Freelancer? Sole Trader? Limited Company? Which Setup Changes What You Report
The structure you pick changes everything—especially your reporting duties. As a sole trader, you’re personally liable. You report via Self Assessment. You pay income tax and National Insurance on profits. Simple. But risky. If things go south, your house is on the line. A limited company is separate. You’re a director. You pay Corporation Tax at 25% (on profits over £250,000; smaller firms pay 19%). You can take salary and dividends. But the reporting? Much more complex. You need annual accounts, a Company Tax Return, Companies House filings. And yes—you still need to tell HMRC you’re trading, even if you’re incorporated.
Now, here’s a nuance most miss: if you incorporate but don’t start trading immediately, you don’t need to register for trading until you actually do. But once you invoice, hire, or sell—game on. And because the company is a legal entity, you must also register with Companies House within three months of incorporation. Two clocks. Two deadlines. That said, for most solopreneurs, starting as a sole trader makes sense. Lower admin. Less paperwork. But you lose limited liability. We’re far from it being a one-size-fits-all decision.
And what about freelancers on platforms like Fiverr or Toptal? Same rules apply. If you’re earning consistently, you’re trading. No exceptions. Some believe marketplace reporting means HMRC already knows. Not true. Platforms may report data under DAC7 (from 2024), but that’s not a substitute for registration. You still need to act. Because HMRC won’t chase you until it’s time to tax you.
Penalties, Risks, and What Happens If You Ignore the Rules
Let’s be clear about this: HMRC are not passive. They cross-check. They use data from banks, platforms, even property records. They spot inconsistencies. And when they do, they act. Penalties aren’t just for late registration. They’re for inaccuracies, underreporting, or failing to keep records. The starting penalty is £100. Then £10 a day after three months. Then 5% of the tax due after six. Then another 5% after 12. It escalates fast.
But the real risk? Reputational. If you’re caught out, HMRC can publicise your details under the “naming and shaming” scheme. Imagine your name, business, and penalty amount online for all to see. That changes everything—especially if you’re in a client-facing role. And audits? They’re rare for small traders, but possible. One red flag—like inconsistent expenses or sudden losses—can trigger a check. Because tax authorities know patterns. They know what typical freelancers spend. They know average profit margins. And they’re getting smarter.
Yet, here’s a personal take: I find this overrated. Most small traders won’t be audited. But that doesn’t mean you ignore the rules. It means you comply to sleep at night. Because the cost of non-compliance isn’t just financial. It’s stress. It’s fear of discovery. It’s scrambling to reconstruct years of receipts from shoeboxes. And that’s exactly where good habits matter. Start clean. Stay clean.
Frequently Asked Questions
Can I delay registration if I’m not earning much?
No. Even if you make £1, you must register within three months. Turnover doesn’t matter. Trading does. And yes, you still need to file a return—even if you made a loss. Because HMRC needs to see the full picture. The threshold for paying tax is the Personal Allowance (£12,570 in 2024/25), not registration.
What if I stop trading? Do I still need to report?
Absolutely. You must file a final tax return for the period you were active. Then inform HMRC you’ve ceased trading. Otherwise, they’ll keep expecting returns. And penalties can still apply. Better to close the loop properly.
Does selling online count as trading?
It depends. Selling old clothes? Probably not. Running an Etsy shop with regular listings, branding, and reinvestment? Definitely. The badges of trade apply regardless of platform. So yes—if it looks like a business, it is one.
The Bottom Line: Don’t Wait Until You’re “Big Enough”
You don’t need to be incorporated, have an office, or hire staff to be a trader. All you need is intent, repetition, and profit motive. And once that’s there, you must tell HMRC within 92 days. Not because it’s “important,” but because the penalty system doesn’t care about your excuses. Register early. Keep records. File on time. It’s not glamorous. It’s not exciting. But it’s the foundation of anything sustainable. Because in the long run, the smallest oversight can snowball into the biggest headache. And that, more than any tax bill, is what keeps smart traders up at night.