Side Hustle Tax Rules 2026: When HMRC Wants to Know About Your Extra Income

The trading allowance

Every individual gets an automatic trading allowance. If your total gross income from self-employment and casual trading is below it in a tax year, you owe no tax on that income and you do not need to tell HMRC. There is no registration and no return.

The allowance covers your combined total from all trading sources, not one activity at a time. Tutoring income and handmade sales are added together and tested against the same allowance.

Each year you choose between using the trading allowance or claiming your actual business expenses. You cannot do both. Where your real costs are small, the allowance usually gives the larger deduction. Where you carry meaningful costs for materials, software or travel, claiming actual expenses may leave you better off, so run it both ways.

Property income has its own separate allowance, which works independently of the trading allowance. Renting out a driveway or storage space is tested against that one. Both allowances are set at fiscal events, so check the current amounts on GOV.UK before you rely on them.

HMRC already has the platform data

Since January 2024, digital platforms operating in the UK have been legally required to collect seller income data and report it to HMRC, under the UK rules that implement the OECD model reporting rules for digital platforms. It is not optional for the platforms and non-compliance is penalised.

The first bulk delivery, covering the 2025 calendar year, reached HMRC in January 2026. It spans marketplaces such as eBay, Etsy, Amazon Marketplace, Vinted and Depop, and gig and rental platforms such as Airbnb, Uber and Deliveroo.

Reporting does not change when tax is due. The same allowances and tests apply as before. What changed is HMRC's ability to cross-reference: a return showing a small trading figure against a platform report showing a much larger one is now visible without anyone opening an enquiry first.

HMRC has started writing to platform sellers whose reported income does not line up with their filings. If a letter arrives, answer it. Correcting an error voluntarily generally costs far less in penalties than waiting for a formal compliance check.

Trading or just selling your own things

Not everything sold online is taxable. HMRC separates selling personal possessions you no longer want from trading, which is buying or making goods with the intention of selling them at a profit. Clearing out a wardrobe on Vinted or selling an old games console is generally not trading.

Trading is judged on the badges of trade: how often you sell, the volume, whether you buy specifically to resell, whether you modify or improve goods before sale, and whether there is a profit motive. Sourcing stock from wholesalers and listing it is trading regardless of how much it earns.

The grey area is drift. Someone who starts by selling their own items and gradually begins sourcing similar items to sell can cross the line without noticing. HMRC looks at the overall pattern rather than a single sale, and the question is whether the activity is carried on with regularity and a view to profit.

Selling your own old sofa is not taxable. Buying furniture at car boot sales, restoring it and reselling it almost certainly is. When in doubt, keep the records: if the total sits under the trading allowance you can still apply it.

The proposed simplified reporting tier

The government has proposed raising the point at which a side hustle triggers a full Self Assessment return. The plan creates three tiers rather than two: income below the trading allowance stays tax free with nothing to report, a middle band stays taxable but is reported through a simplified online process instead of a full return, and income above the upper level continues to require full Self Assessment.

The stated aim is to take a few hundred thousand people out of the Self Assessment system while leaving the tax itself unchanged. For casual sellers this is an administrative simplification, not a tax cut.

This is not law yet. It is expected to take effect no earlier than a future tax year and still needs to pass through Parliament, and the amounts involved are the sort that move between announcement and implementation. Until it is in force, register and file under the current rules if you are over the current threshold, and check GOV.UK for the confirmed figures and start date.

Registration and filing deadlines

If your gross self-employment income exceeds the trading allowance in a tax year, you must register for Self Assessment. The registration deadline is 5 October following the end of that tax year. When you register, HMRC issues a Unique Taxpayer Reference, which you will need every year afterwards.

The online filing deadline is 31 January following the end of the tax year, and it is also the payment deadline for the tax owed. A paper return has an earlier deadline of 31 October. Late filing triggers an automatic penalty and late payment accrues interest from the day after the due date.

If your bill is large enough relative to tax already deducted at source, HMRC will require payments on account: advance instalments towards next year's bill, due on 31 January and 31 July. The first year this happens is the one that surprises people, because the January payment covers the balance for one year plus the first instalment for the next.

Staying on top of it

The habit that matters most is recording income as it arrives rather than reconstructing a year of transactions in January. Platform payouts, bank transfers, cash and invoices all need to land somewhere, whether that is a spreadsheet, an app or accounting software.

At the end of the tax year, decide between the trading allowance and actual expenses by comparing the two. If your gross total is under the allowance there is nothing further to do. If it is over, work out which method gives the lower taxable figure.

Keep the evidence. HMRC requires self-employed records to be retained for several years after the filing deadline, and the exact period is published on GOV.UK. Digital copies are fine: receipts, invoices, bank statements and platform payment confirmations.

Taxmo tracks income and expenses through the year, categorises transactions and keeps a running tax estimate, which is the point at which a side hustle stops being a January problem.

Common questions