When should I tell HMRC that I’m self-employed

If you are asking when you should tell HMRC that you are self employed, the answer is sooner than you think. The formal deadline is 5 October following the end of the tax year in which your self employment began, yet registering early avoids stress and gives you time to set up payments properly. The tax year runs from 6 April to 5 April the following year, so your dates hinge on that window¹².

At Pennine Accounting, we help sole traders and small limited companies across Rochdale, Oldham, and West Yorkshire decide the right point to notify HMRC, get set up for Self AssessmentHMRC’s system for reporting untaxed income through an annual return. You calculate tax due and pay by 31 January after the tax year., and put aside the right amounts for tax and National InsuranceSelf employed people usually pay Class 2 and Class 4 National Insurance through Self Assessment.. The headline rule is clear, register by 5 October after the tax year you started².

When exactly must you tell HMRC?

HMRC expects you to register for Self Assessment by 5 October following the end of the tax year in which you became self employed. If you started on any date between 6 April 2023 and 5 April 2024, you must register by 5 October 2024 to avoid a potential failure to notify penalty²³. If you miss this date, HMRC may still accept your registration, but they can impose penalties and may adjust your filing deadline to three months from the date they contact you⁴.

Key dates to keep in view are the 31 October paper filing date, the 31 January online filing and payment date, and the 31 July second payment on accountAdvance payments towards your next year’s tax bill. Many traders make two payments on account, 31 January and 31 July.. These sit alongside the 5 October registration date¹⁴.

Quick checklist to anchor your timeline:

• Register date: Tell HMRC by 5 October after the tax year you started self employment².
• Paper return: File by 31 October if you prefer paper⁴.
• Online return and pay: File online and pay any tax due by 31 January⁴.
• Payments on account: If required, pay 31 January and 31 July.

Should you register as soon as you start trading?

Yes, in most cases. Although HMRC allows you to register any time up to 5 October after the tax year ends, early registration means your Unique Taxpayer ReferenceA ten digit number HMRC issues after you register. You need it to file your return and for most communications with HMRC. arrives sooner, your online account is ready, and you can budget accurately. Early action also avoids last minute delays in January, which is often when people get stuck waiting for codes to arrive in the post during HMRC’s busiest period¹.

There are a couple of edge cases. If your total trading income for the year is at or below the trading allowance of £1,000, you may not need to register, though you might choose to if you want to claim expenses over that allowance. If in doubt, ask for advice before the 5 October point. Our clients in Littleborough, Rochdale, and Oldham tell us the calm comes from clarity, not from cutting it fine.

Real world examples, what your date looks like

Use these examples to see your exact registration and filing dates. We have included a few common start dates to show how the 5 October rule works in practice.

What actually triggers the need to register?

HMRC wants you to register once you start earning from your business activities, even if your first invoices are small. Income from freelancing, contracting, or side work that is more than a hobby usually means you have started trading and should register without delay³.

Typical triggers include:

1. Your first paid job or sale. Money received for services or goods shows trading has begun.
2. Regular activity with a profit motive. You are seeking to make a profit, not only selling personal items.
3. Advertising or pitching for work. Promotional activity suggests you have started a business.
4. Signing a client contract. Even before cash arrives, the business has commenced.
5. Crossing the £1,000 trading allowance. At this point, registration is usually required to report income properly.

Register in five simple steps

These steps keep it tidy and minimise admin headaches.

Common mistakes and how to avoid them

Rushing in January, assuming the trading allowance removes the need to register, or mixing personal and business banking causes friction later. Small habits solve big problems: open a separate account, store receipts digitally, and diarise dates with calendar reminders linked to 5 October, 31 October, and 31 January so nothing slips.