Gone over £1,000? Don't panic.

Here's exactly what to do next

The whole HMRC process, start to finish, in about a minute. No jargon.

▶ Free walkthrough · no sign-up · not tax advice

← Not sure you even owe tax? Check the free calculator first

Step 1 · Tell HMRC

Register for Self Assessment

Hop on the HMRC app or GOV.UK and tell them you've been trading. It's free and takes about 10 minutes.

Do this by 5 October
✉ Letter from HMRC
YOUR UTR
● ● ● ● ● ● ● ● ● ●
Step 2 · Wait for the post

Your UTR letter arrives

HMRC posts you a 10-digit UTR number (about 10 working days), plus a second letter with an activation code.

Arrives in ~10 days
✓
Step 3 · Switch it on

Activate your account

Log into the HMRC app, pop in your UTR and activation code. Now you can do everything from your phone.

📄 Your tax return
SOLD & COSTS
£ from FlipSorted
Step 4 · Fill it in

Complete your return online

Enter what you sold and what it cost you. This is where FlipSorted's totals drop straight in — no digging.

📨
Step 5 · Send it

File your return

Submit it online. One tap and HMRC has everything they need from you for the year.

File by 31 January
Step 6 · Pay

Pay what you owe

Pay your bill in the HMRC app straight from your bank. Done — sorted for another year. 🎉

Pay by 31 January
Step 1 of 6

Key dates

5 Oct 2026
Register with HMRC by
31 Jan 2027
File & pay by

HMRC asks you to register by 5 October — that's simply you putting your hand up to say "I'm someone who needs to pay tax this year." The return itself, and the payment, are then due by the following 31 January. So for money you made in the 2025/26 tax year (6 April 2025 – 5 April 2026), you'd register by 5 October 2026 and then file & pay by 31 January 2027.

Prefer it written down?

The same six steps, to save or come back to.
  1. Tell HMRC you're trading.

    Register for Self Assessment on the HMRC website or app — by 5 October after the tax year you went over £1,000.

  2. Wait for your UTR letter.

    HMRC posts your 10-digit UTR number (~10 working days), and usually a separate letter with an activation code.

  3. Activate your online account.

    Log into the HMRC app / Government Gateway and enter your UTR and activation code.

  4. Fill in your tax return online.

    Declare what you sold and your costs. (FlipSorted gives you these totals ready to copy in.)

  5. File your return.

    Submit it online by 31 January after the tax year. Check deadlines →

  6. Pay your bill.

    Pay what you owe by 31 January too — easiest in the HMRC app via your bank.

Never want to scramble in January again?

Track your sales all year with our free tracker — it keeps a running total and warns you the moment you cross £1,000, with your figures ready for the return.

Start tracking — free →
This is a plain-English guide to the public HMRC process — it is not tax advice and FlipSorted is not affiliated with HMRC. Your own situation may differ (and rules change). Always confirm on GOV.UK or with an accountant.