Side Hustle Tax UK 2026: When Do You Pay?

Quick answer

If your side hustle brings in £1,000 or less of gross income in a tax year, the trading allowance means you owe no tax and do not even need to tell HMRC. Cross £1,000, and you normally have to register for Self Assessment, file a return, and pay tax — but only on your profit (income minus allowable expenses, or minus the £1,000 allowance itself, whichever helps you more).

The wrinkle most people miss is that side income does not get its own fresh tax-free allowance if you already have a job — it stacks on top of your salary and is taxed at whatever your highest rate is. And with digital platforms now sharing earnings data with HMRC, the old assumption that small online income flies under the radar no longer holds. This guide explains the thresholds, when to register, how the tax is actually worked out, and the records to keep.

The £1,000 trading allowance

The trading allowance is the side hustler's best friend. It lets you earn up to £1,000 of gross trading income in a tax year completely tax-free, with no obligation to register or report it.

Two crucial details:

• It is based on gross income, not profit. If you sell £1,100 of crafts but only made £200 profit after materials, you have still exceeded the £1,000 allowance because the test is on the £1,100 of total income.
• It covers trading and miscellaneous income — selling goods you make or buy to resell, freelancing, tutoring, gig work, content creation, and similar. (There is a separate £1,000 property allowance for small amounts of rental-type income.)

If your total side income for the year stays at or below £1,000, you can stop reading here for tax purposes — there is nothing to declare. Casual selling of your own unwanted personal possessions (clearing out your wardrobe on a marketplace) is generally not "trading" at all and is not taxable, though buying to resell is trading.

When you must register for Self Assessment

Once your gross side-hustle income exceeds £1,000 in a tax year, you normally need to register for Self Assessment as self-employed. The deadlines matter:

• Register by 5 October following the end of the tax year in which you went over (the UK tax year runs to 5 April).
• File your return and pay any tax by 31 January after the tax year.

So if you crossed £1,000 in the 2025/26 tax year, you would register by 5 October 2026 and file and pay by 31 January 2027. Missing the registration or filing deadlines triggers penalties even if little or no tax is due, so do not leave it.

Registration gives you a Unique Taxpayer Reference and brings your side hustle into the same return as your other income.

How the tax is actually worked out

Here is the part that catches people out. If you have a PAYE job, your salary has probably already used up your £12,570 personal allowance and a chunk of your basic-rate band (which runs to £50,270). Your side-hustle profit is added on top, so it is taxed at your highest marginal rate:

• If your salary plus side profit stays within the basic-rate band, the profit is taxed at 20%.
• If it pushes you over £50,270, the slice above is taxed at 40%.
• Very high earners can hit 45% above £125,140.

On top of income tax, self-employed profits above the relevant threshold attract Class 4 National Insurance. So a higher-rate employee with a profitable side hustle could be handing over 40% income tax plus Class 4 NI on the profit — worth knowing before you spend it.

You can reduce the taxable figure two ways, and you pick whichever is better:

1. Deduct the £1,000 trading allowance from your gross income (simple, no need to track expenses), or
2. Deduct your actual allowable expenses (materials, fees, mileage, a share of home costs) if they come to more than £1,000.

You cannot do both. For a low-cost hustle, the £1,000 allowance usually wins; for one with real expenses, deducting actual costs is better. Work out the tax on your combined income with the

, and see how the profit sits on top of your salary using the .

A worked example

Take Sam, who earns £45,000 in a PAYE job and runs a weekend photography side hustle that brings in £6,000 gross, with £1,500 of genuine costs (gear hire, travel, editing software).

• Choosing actual expenses (£1,500) beats the £1,000 allowance, so Sam's taxable profit is £6,000 − £1,500 = £4,500.
• Sam's salary (£45,000) leaves about £5,270 of basic-rate band before the £50,270 higher-rate threshold. So most of the £4,500 profit is taxed at 20%, with none tipping into higher rate this year.
• Class 4 National Insurance also applies to the profit above the threshold.

If Sam's salary had been £49,000, much of the side profit would have spilled over £50,270 and been taxed at 40% — the same hustle, a very different tax bill, purely because of the salary underneath it. This is why you must look at your total income, not the side hustle in isolation. Model your combined position with the

.

HMRC can see more than you think

The days of assuming small online income is invisible are over. Under data-sharing rules, digital platforms — online marketplaces, short-term letting sites, food-delivery and ride apps, freelancing platforms — now report seller and earner information to HMRC. That includes how much you earned and your account details.

This does not change the tax rules — the £1,000 allowance and the genuine sale of personal possessions still apply exactly as before — but it does mean that income above the allowance is increasingly visible. The safe approach is simple: keep records, and declare what you are required to. HMRC matching platform data against undeclared income is now a real risk, not a hypothetical one.

Selling possessions versus trading

One of the most reassuring things to understand is the line between selling your own stuff and trading, because they are taxed completely differently.

If you clear out your wardrobe, sell an old sofa, or list possessions you no longer want on a marketplace, you are generally not trading — you are disposing of personal belongings, and the proceeds are not taxable income at all. (The only caveat is Capital Gains Tax on individual items worth more than £6,000, which rarely affects everyday second-hand selling.) You do not need to declare this however much you sell, because it is not a business.

You cross into trading when you buy or make things with the intention of selling them at a profit, or provide services for payment, on a repeated and organised basis. Buying job lots to flip, making crafts to sell, reselling sneakers, dog-walking, freelancing — these are trading, and the £1,000 allowance and Self Assessment rules apply.

HMRC looks at the badges of trade to decide which side of the line you are on: how often you sell, whether you buy specifically to resell, whether you modify items to make them more saleable, and your intention. The practical takeaway: a one-off declutter is nothing to worry about; a regular buy-to-resell operation is a business, even if it feels like a hobby.

Class 2 and Class 4 National Insurance

Income tax is not the only deduction on side-hustle profit. Self-employment also brings National Insurance into play, and it works differently from the NI on your salary.

• Class 4 NI is charged as a percentage of your profits above an annual threshold. It is the main self-employed NI and is calculated through your Self Assessment return alongside income tax.
• Class 2 NI historically was a small flat weekly charge, but the system has been changing so that lower-profit self-employed people are treated more favourably and may not pay it as a separate charge while still receiving NI credits towards the State Pension.

The key point for a side hustler is that your salaried job already pays Class 1 NI, and your self-employment can additionally attract Class 4 on its profits. The two do not cancel out — you can pay employee NI on your salary and self-employed NI on your side profits in the same year, though there are annual maximums that stop you overpaying across all classes. Because the rules here have been in flux, check the current thresholds, and let the

handle the interaction for you rather than estimating by hand.

Payments on account: the January surprise

Here is the trap that catches many first-time Self Assessment filers off guard. If your Self Assessment tax bill is above a modest threshold, HMRC asks you to make payments on account — advance payments towards next year's bill.

In practice, this means that in your first January of filing, you may have to pay not just the tax due for the year that has ended, but also half of it again as an advance for the current year, with the second half due the following July. So a £2,000 bill can feel like £3,000 in January. It is not extra tax — it is prepayment that reduces next year's bill — but it is a genuine cash-flow shock if you are not expecting it.

The lesson is simple: when you estimate your side-hustle tax, budget for the possibility of payments on account in that first year, and set aside more than the headline figure. The

gives you the underlying tax due so you can plan the cash flow before HMRC's demand lands.

When your side hustle becomes a main business

If your side hustle grows, two further thresholds come into view. The first is the VAT registration threshold of £90,000 of taxable turnover — once your side-hustle sales pass that on a rolling 12-month basis, you must register for VAT regardless of your day job. The second is the decision about business structure: most side hustles run as a sole trader, but as profits grow some people consider a limited company for tax efficiency and limited liability. That is a bigger decision with its own trade-offs, and it only tends to make sense once profits are substantial and sustained.

For most side hustlers, though, none of this applies yet — you are a sole trader earning a few thousand pounds on top of a salary, and the trading allowance plus a straightforward Self Assessment return is all you need. Keep an eye on the thresholds as you grow, and revisit your structure if and when the numbers justify it. Model your combined position as the side hustle scales with the

.

Records to keep

Good records make Self Assessment painless and protect you if HMRC asks questions. Keep:

• Income records — every sale or payment, with dates.
• Expense receipts — materials, fees, equipment, travel, a reasonable share of home and phone costs.
• Platform statements — the figures platforms report to HMRC.
• Mileage logs if you claim vehicle costs.

Keep them for at least the period HMRC requires (generally several years). A simple spreadsheet is enough for most side hustles; the goal is to be able to show how you arrived at your declared profit.

A quick action plan

1. Track your gross side income through the tax year.
2. Under £1,000? Nothing to do — the trading allowance covers you.
3. Over £1,000? Register for Self Assessment by 5 October after the tax year.
4. Choose the £1,000 allowance or actual expenses — whichever gives the lower taxable figure.
5. Estimate the tax on your combined salary and profit with the
   ƒ

   Try the calculator

   Self-Employed Tax Calculator

   Calculate income tax, Class 2 and Class 4 National Insurance for self-employed and sole traders for 2025/26.

   self-employed tax calculator→
   so there are no surprises in January.
6. Set the money aside and file and pay by 31 January, planning around it with the
   ƒ

   Try the calculator

   Take-Home Pay Calculator

   Calculate your net salary after income tax, National Insurance and student loan deductions.

   take-home pay calculator→
   .

The bottom line

Side-hustle tax in 2026 comes down to one threshold and one principle. The threshold is the £1,000 trading allowance: below it, you owe nothing and report nothing; above it, you register for Self Assessment and declare the income, paying tax only on profit. The principle is that side income stacks on top of your salary and is taxed at your highest rate, so always look at your total income. With platforms now reporting earnings to HMRC, the smart move is to keep clean records and declare what you should — the cost of getting it wrong now outweighs any temptation to leave it off.

This is general information, not tax advice. Thresholds and rules change, and your position depends on your total income; check gov.uk or speak to an accountant if you are unsure.