Check whether you need to file, confirm your route and deadline, and make a short list of missing records.
THE SOURCED NEWS
Two filing dates to keep separate
HMRC’s reminder concerns the 2025 to 2026 tax year. Its January deadline is for online filing and paying tax owed, while its further information gives 31 October 2026 for paper returns. Use the deadline on any HMRC notice that applies to you.
The release links an official checker for people unsure whether they need a return. It also says people signed up to Making Tax Digital for Income Tax still need to submit their Self Assessment return in the usual way and pay tax owed by 31 January 2027.
SELLERBUNDLE PRACTICAL ANALYSIS
SellerBundle: build a small records checklist
Start with the period you are preparing and the records your accountant or filing process needs. Gather sales and payment records, supplier documents and relevant business expenses. Keep a separate list of anything missing so you can ask specific questions.
Reconcile totals rather than assuming a marketplace sales figure is the same as the money reaching your bank. Record fees, refunds and other adjustments clearly. If you are unsure how an item should be treated, ask for advice before submitting; a tidy evidence folder makes that conversation easier.
SELLERBUNDLE PRACTICAL ANALYSIS
Leave time for questions and payment
Choose an early date to finish gathering records and another to review the return. Put the confirmed payment amount and due date into your cash-flow plan when known. Keep an estimate clearly labelled until the calculation is checked.
Reach the official service through GOV.UK rather than an unexpected message. HMRC warns about impersonation scams in this release. Keep sign-in details private, and save your filing acknowledgement and payment record once the relevant steps are complete.
GO TO THE ORIGINAL
Check the sources.
HMRC: 23 October Self Assessment reminder, online and paper deadlines ↗
Published 23 Oct 2026
GOV.UK: check whether you need a 2025 to 2026 Self Assessment return (undated guidance) ↗
Published date not stated
This is an original SellerBundle explanation with practical editorial suggestions. Check current official terms and suitability before changing your business processes.