Do you need to submit a self-assessment tax return by the end of January 2026?

CREATED BY ALISON MEAD Published: 11/01/2026 @ 09:00AM #self-assessmenttaxreturn #SelfAssessment #HMRC #TradingAllowance #SideHustle #UKTax

Wondering if a self-assessment tax return is due by the end of January 2026? This explains who typically needs to file, how the £1,000 trading allowance fits around the 5th of April, and why HMRC may still expect a return if someone registered or filed before ...

Self-assessment tax return, Numbers and forms to fill, An annual task?

Most people only need to file a self-assessment tax return when there's a clear reason HMRC expects one, and it usually comes down to what happened in the tax year that ended on the previous 5th of April. The simplest way to think about it is that HMRC cares about what was earned in that tax year, and whether the person's circumstances mean a return is required.

For many side hustles, the £1,000 trading
allowance is the pivot point!

If someone's total trading income for the tax year to the 5th of April 2025 went over £1,000, that commonly puts them into self-assessment territory for that year, and a self-assessment tax return may be needed by the January 2026 deadline.

The timing around the tax year-end matters more than people expect. If someone started selling, freelancing, or creating content before the 5th of April 2025, but did not exceed the £1,000 trading allowance by that date, they generally won't be counting that same income again in the next tax year; from the 6th of April 2025 it's a fresh tax year, so the running total effectively starts again for measuring what happens in 2025/26.

Where it gets less forgiving is registration. If someone registered for self-employment and told HMRC their business started before the 5th of April 2025, HMRC may still expect a self-assessment tax return for that year even if the person later paused, gave up, or earned less than expected.

The logic is straightforward: registration signals to HMRC that there is a business to report, and HMRC systems often continue to expect a return until the position is formally updated.

The same 'expectation' issue crops up for people who have filed before. If someone has been in self-assessment previously, HMRC may continue to issue filing requirements year after year unless the person has specifically told HMRC they no longer need to submit returns.In practice, that means someone can be below the trading allowance and still be chased for a self-assessment tax return simply because their record still says they're in the system.

For anyone who is unsure whether they crossed the £1,000 line, or just wants to avoid guesswork, good records tend to resolve the question quickly. A simple spreadsheet that logs income and expenses can make it obvious whether a self-assessment tax return is needed, and it can include optional sections for more niche situations, such as TikTok affiliates receiving gifted samples, which can be ignored if it's not relevant.

Ultimately, the January deadline is only stressful when someone waits for certainty to appear on its own!

If they check what was earned up to the 5th of April 2025, confirm whether they registered (or are still registered) for self-employment, and make sure HMRC isn't still expecting filings from previous years, they'll know whether a self-assessment tax return needs to be submitted by the end of January 2026.

Please note: If you are unsure of your numbers, I have a spreadsheet for self-employment side hustles that you can download to verify. It includes an area for TikTok affiliates who get samples, though you can ignore that page if not needed.

Click here to visit Payhip and discover more.

Until next time ...

ALISON MEAD
I'm your Bookkeeping Buddy: Discover more by clicking here!

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About Alison Mead ...
Alison loves bookkeeping and supporting bookkeepers. She has been helping clients to be better bookkeepers in Sage 50 for over 24 years and has been Xero Accredited in accounts and payroll for a number of years too. She specialises in a very unique hand-holding method of training, helping bookkeepers and business owners to use their accounts software as and when they need support in setting up and producing their invoices, reports and financial information. Alison combines her role at Silicon Bullet with her Forever Living network marketing businesses and is often to be seen at business networking meetings as she likes to keep busy. You know what they say: if you want something done well ask a busy person!

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