This is one of the most common questions people ask once a side hustle starts bringing in real money, and it’s a fair one to be unsure about, since the answer depends on more than just how much you’re earning. This guide walks through exactly how to work out whether you need to register, how to actually do it, and what happens if you’ve already missed the point where you should have.
This is general information rather than personal tax advice. Always check GOV.UK or speak to an accountant if your situation is more complicated than the examples covered here.
The Short Answer
If your side hustle earns more than £1,000 in gross income during a tax year, which runs from 6 April to 5 April, you generally need to register as self-employed with HMRC. Below that figure, covered by what’s called the trading allowance, you usually don’t need to register or declare anything at all.
That’s the simple version. The more useful version accounts for a few situations where the answer isn’t quite so clear-cut.
Working Out If You’re Actually “Trading”
Before the £1,000 figure even matters, it’s worth checking whether what you’re doing counts as trading in HMRC’s eyes at all, since not everything that brings in money is treated as a trade.
Generally counts as trading:
- Freelance work of any kind, from writing to design to tutoring
- Selling items you’ve made yourself, such as handmade crafts or baked goods
- Buying items specifically with the intention of reselling them for a profit
- Providing a service, such as dog walking, gardening, or cleaning
- Renting out equipment, such as tools or a camera, on a casual but repeated basis
Generally doesn’t count as trading:
- Selling your own unwanted personal possessions, such as clearing out your wardrobe or old furniture you originally bought for yourself, even if the total adds up to a meaningful amount over a year
- A genuinely one-off sale of something you owned personally, rather than an ongoing pattern of buying and selling
The distinction matters because HMRC’s rules are built around the idea of trading with the intention of making a profit, not simply disposing of things you already owned. If you’re not sure which category your activity falls into, it’s worth checking HMRC’s guidance directly or using their online checker tool, since getting this wrong in either direction, registering when you didn’t need to, or not registering when you did, causes unnecessary hassle.
If You’re Under £1,000: What You Actually Need to Do
If your gross side hustle income, meaning the total you receive before any costs are taken out, stays at or below £1,000 for the tax year, you’re covered by the trading allowance and generally don’t need to register with HMRC or file anything for that income.
A couple of things still worth doing anyway, even though you’re not required to:
- Keep a simple record of what you’ve earned and when, even informally, since it’s useful if your circumstances change partway through the year or if HMRC ever asks a question about your platform income
- Check your total across everything you’re doing combined, not just one platform or activity, since the £1,000 limit applies to your side hustle income as a whole, not separately per platform
If You’re Over £1,000: The Actual Registration Process
Once your gross side hustle income goes over £1,000 in a tax year, here’s what registering actually involves.
Step one: register for Self Assessment. This is done online through GOV.UK, and you’ll need your National Insurance number and some basic details about your side hustle. You’ll be asked to set up a Government Gateway account if you don’t already have one, which becomes your main portal for managing your tax affairs going forward.
Step two: note your deadline. You need to register by 5 October following the end of the tax year in which you went over £1,000. For example, if you crossed the threshold at any point between 6 April 2025 and 5 April 2026, you need to register by 5 October 2026.
Step three: wait for your Unique Taxpayer Reference. After registering, HMRC will send you a UTR, a ten-digit number that identifies you for tax purposes and that you’ll need every time you deal with your Self Assessment return going forward. This can take a couple of weeks to arrive, so it’s worth registering as soon as you realise you’ve gone over the threshold rather than waiting.
Step four: file your Self Assessment return. The deadline for filing online and paying any tax owed is 31 January, covering the tax year that ended the previous April. So for income earned in the 2025/26 tax year, the return and any payment are due by 31 January 2027.
What Happens If You Register Later Than You Should Have
If you realise you’ve gone over £1,000 in a previous tax year but never registered, the right move is to register as soon as possible rather than waiting or hoping it goes unnoticed. HMRC can charge penalties for late registration, but registering promptly and being upfront about the delay generally reduces the risk of additional charges compared to leaving it even longer.
It’s also worth knowing that since January 2024, digital platforms including eBay, Vinted, Etsy, Airbnb, and Uber have been legally required to report seller and provider earnings data directly to HMRC. This means HMRC frequently already has visibility into platform-based income, even for people who haven’t registered, so assuming smaller amounts will simply go unnoticed is no longer a safe assumption.
Does Registering Mean I’ll Definitely Owe Tax?
Not necessarily. Registering for Self Assessment and owing tax are two different things. Once registered, you’ll calculate your taxable profit, either by deducting the flat £1,000 trading allowance from your gross income, or by deducting your actual business expenses instead, whichever results in a lower figure. If your resulting profit, combined with any other income you have, stays within your tax-free Personal Allowance for the year, you may end up owing little or nothing, even though you’re required to file the return.
This is a common source of confusion: people sometimes avoid registering because they assume it automatically means a tax bill, when in reality registration is simply the process of declaring the income, and the actual tax owed depends on your full financial picture for the year.
Registering While You’re Also Employed
A lot of side hustles run alongside a normal full-time job, and this doesn’t change the basic rule. If your side hustle income goes over £1,000, you still need to register for Self Assessment, even though your main job’s tax is already being handled automatically through PAYE. Your side hustle income is assessed and taxed separately through your Self Assessment return, and it’s added to your overall income when working out which tax bands apply, which can occasionally push some of your combined income into a higher rate if your side hustle earnings are substantial.
Should I Register Even If I’m Under £1,000?
In most cases, there’s no requirement to register below the threshold, and doing so simply creates extra paperwork for no benefit. There is one situation where it can still make sense: if your side hustle involves meaningful costs, and you’re currently making a loss rather than a profit, registering voluntarily allows you to formally record that loss, which can sometimes be used to reduce tax owed elsewhere or carried forward against future profits. This is a more specific situation and worth discussing with an accountant if it applies to you, rather than assuming it’s the right move by default.
A Simple Way to Check Where You Stand
If you’re genuinely unsure whether you need to register, HMRC provides a free, anonymous online tool specifically designed to help people with side hustles work out whether and when they need to report their income. Running your situation through this before making assumptions either way is a quick, low-effort way to get clarity, particularly if your circumstances involve more than one type of side income or you’re close to the £1,000 threshold and not sure exactly where you land.
Registering vs Setting Up a Limited Company
For the vast majority of side hustlers, registering as a sole trader through Self Assessment is the right route, and it’s important not to confuse this with setting up a limited company, which is a separate, more involved legal structure. As a sole trader, you and your business are legally the same entity, which keeps the admin relatively simple. A limited company is a distinct legal entity from you personally, involves registering with Companies House as well as HMRC, and comes with additional ongoing obligations like filing annual company accounts.
Most side hustles never need to become a limited company, since the extra admin only tends to pay off once your income and specific circumstances make the tax efficiency worthwhile. If you’re just starting out, defaulting to sole trader registration through Self Assessment is almost always the simpler and more appropriate choice.
Keeping Records From Day One
Whether or not you’re required to register, building the habit of tracking your income and expenses from the very start makes everything easier later, particularly if your side hustle grows unexpectedly quickly.
A simple approach that works for most people:
- Keep a basic spreadsheet, or use a simple app, logging what you earned, when, and from which platform or client
- Save receipts or screenshots for any expenses you might want to claim later, such as materials, software subscriptions, or platform fees
- Separate your side hustle money from your personal spending where practical, even if that just means using a dedicated section of your existing bank account rather than mixing everything together
This habit matters more than it might seem, since trying to reconstruct months of income and expenses from memory right before a filing deadline is far more stressful than keeping a simple running record as you go.
What Counts as an Allowable Expense
If you choose to claim actual expenses rather than the flat £1,000 trading allowance once you’re registered, it’s worth knowing broadly what you can and can’t deduct. Generally allowable expenses include things directly related to running your side hustle, such as materials and stock, platform or marketplace fees, a reasonable portion of home costs like internet if you work from home, and any specific equipment or software needed to do the work. Personal expenses unrelated to the activity, or costs that would exist regardless of your side hustle, generally aren’t deductible. If you’re unsure whether a specific cost qualifies, HMRC’s guidance on allowable expenses for the self-employed is worth checking, or it’s a reasonable question to put to an accountant once your side hustle involves meaningful costs.
Frequently Asked Questions
What if I’m not sure whether my activity counts as trading? HMRC provides a free online checker specifically designed to help with this, and it’s worth using if you’re genuinely unsure, rather than guessing in either direction.
Can I register partway through a tax year? Yes, registration isn’t tied to a specific point in the year. You register once you realise your income has gone, or is likely to go, over £1,000 for that tax year, and the 5 October deadline simply marks the latest point by which you must have done so.
Does registering as self-employed affect my main job’s tax? No, your employed income continues to be taxed through PAYE exactly as before. Your self-employed income is assessed separately through Self Assessment, though both are considered together when working out which overall tax band your combined income falls into.
What if my side hustle income varies a lot month to month? This is completely normal and doesn’t change the registration rule itself. What matters is your total gross income across the whole tax year, not how evenly it’s spread out, so a side hustle that earns very little most months but has one particularly good month can still tip you over the £1,000 threshold for the year as a whole.