If you began selling on eBay, Etsy, Vinted, Amazon, TikTok Shop or your own Shopify store between 6 April 2025 and 5 April 2026, and your sales before costs came to more than £1,000, you need to register for Self Assessment by 5 October 2026. HMRC launched a faster online registration service on 9 September that issues your Unique Taxpayer Reference (UTR) within 72 hours instead of up to 15 days by post, so there is no reason to leave it until the last week.
Who has to register
The test is gross trading income, meaning total sales before you deduct stock, postage, platform fees or anything else. Over £1,000 in the tax year and you register. Under £1,000 and the trading allowance covers you, so there is nothing to declare and nothing to pay. HMRC's announcement of the new service restates the rule and adds that anyone with untaxed income over £2,500 from other sources has to register too.
The £1,000 figure catches people out because it is sales, not profit. A seller who bought £900 of stock and sold it for £1,200 has made £300 and still has to register. The government has said it plans to raise the reporting threshold to £3,000 later in this parliament, but that has not happened, so £1,000 is the number for 2025-26.
What the new registration service changes
Registration has not become optional or later. What has changed is the wait. The form now pre-fills the details HMRC already has, lets you save and come back, and confirms by email or text when it is done. The UTR appears in your online account within 72 hours, where the postal route took up to 15 days and left many first-year sellers reaching January with a return to file and no reference number to file it under.
Without a UTR you cannot submit a return, set up a payment plan or authorise an accountant to act for you. As HMRC's Myrtle Lloyd put it in the announcement: "Anyone new to Self Assessment may not realise they need to register before they can submit their tax return."
HMRC already has your platform data
Since January 2025 UK marketplaces have sent HMRC an annual report on their sellers. eBay, Etsy, Vinted, Depop and Amazon report anyone who made 30 or more sales in a calendar year, or received more than €2,000 (about £1,700), including name, address, date of birth, tax reference where held and total takings less fees, quarter by quarter. The 2025 data reached HMRC by 31 January 2026 and you should have received a copy from each platform. HMRC's guidance for sellers says being reported does not itself mean you owe tax, but it does mean HMRC can see who sold more than £1,000 and has not registered. Registering by 5 October puts you on the right side of that match before any letter arrives.
What happens if you miss 5 October
The penalty for telling HMRC late is a percentage of the tax still unpaid on 31 January. Register late but file and pay in full by 31 January 2027 and the penalty is usually nil. Miss the January deadline as well and the late notification penalty is added to the £100 late filing penalty that applies from 1 February whether or not any tax is due. The bigger practical problem is time: a registration in January leaves you waiting for a UTR as the filing deadline passes.
What your first bill looks like
Take a seller who started on eBay and Etsy in June 2025 alongside a £30,000 salary. Sales for the year were £18,000, stock and postage cost £11,000, so the profit is £7,000. As a basic rate taxpayer the income tax is 20% of £7,000, which is £1,400. Class 4 National Insurance does not apply because profits are below £12,570, and the Class 2 credit towards the state pension comes at no cost at this level of profit.
The amount due on 31 January 2027 is not £1,400. Because the bill is over £1,000 and less than 80% of the seller's total tax was collected through PAYE, HMRC also asks for a first payment on account towards 2026-27 of half the bill, £700. The total payable on 31 January 2027 is £2,100, with another £700 due on 31 July 2027. Payments on account are the part of the first year that new sellers rarely budget for.
The same 2025-26 return decides whether you join Making Tax Digital for Income Tax. If your self-employment and property turnover for 2025-26 was over £30,000, HMRC's timetable puts you into quarterly digital reporting from 6 April 2027, so a seller who cleared £35,000 of sales in their first year needs compatible software in place for 2027-28.
Three things to do this month
Register through gov.uk and note the UTR when it arrives in your online account. Download the 2025-26 sales and fee reports from every platform you sold on, because the payout that reached your bank is sales less fees less refunds, and your return needs each of those separately. Then decide whether to claim actual expenses or the £1,000 trading allowance. If stock, postage and fees came to more than £1,000, actual expenses win, and that will be true for almost every seller who is buying to resell.
If you set up a limited company instead, the company registers for Corporation Tax and you may still need a personal return for dividends, so the 5 October date can apply to directors too.
Frequently asked questions
Do I need to register for Self Assessment if I sell on eBay or Vinted?
Only if you are trading, meaning buying or making items to sell on, and your gross sales in the tax year were over £1,000. Selling your own second-hand belongings is not trading and does not need to be reported, whatever the platform sends to HMRC.
What happens if I miss the 5 October registration deadline?
You can still register, and if you file and pay everything due by 31 January 2027 the late notification penalty is usually nil. Leave it later and you risk having no UTR when the filing deadline arrives, which brings a £100 late filing penalty even if no tax is due.
How long does it take to get a UTR now?
HMRC says the new online service, launched on 9 September 2026, issues the UTR to your online account within 72 hours. The old postal route took up to 15 days.
Will HMRC know about my Etsy or eBay sales?
Yes, if you made 30 or more sales or took more than about £1,700 in a calendar year. Platforms report those sellers to HMRC by 31 January each year and send you a copy of what they reported. Being reported does not on its own mean you owe tax.
Next steps
Our guide to starting an ecommerce business covers the sole trader and limited company choice, VAT registration and the records to keep from day one. If you started selling this year and want your registration, first return and payments on account handled before January, book a discovery call.
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