Registering Late For Self-Employment: What Are The Tax Implications?
Starting a self-employed business is exciting.
You have clients to find, work to deliver, prices to set, software to choose, bank accounts to open and probably a hundred other things competing for your attention.
Registering with HMRC may not feel urgent at the start, especially if the business is still small or you are unsure how much money you will make.
But leaving it too long can become expensive.
Late registration can lead to backdated tax returns, interest, penalties and, in some cases, VAT or Making Tax Digital issues too.
When do you need to register?
The key starting point is the trading allowance.
If your gross trading income is more than £1,000 in a tax year, you will usually need to tell HMRC and register for Self Assessment.
You do not normally have to register on day one of trading. The key deadline is 5 October after the end of the tax year in which you needed to register.
For example, if you started trading during the 2025/26 tax year and your income meant you needed to register, you would usually need to notify HMRC by 5 October 2026.
Miss that deadline, and you are potentially into late registration territory.
Does late registration always mean a penalty?
Not always.
HMRC will usually look at whether tax was lost because you failed to notify them.
If no tax was unpaid, there may be no penalty. But if tax was due and HMRC believes you should have registered earlier, they may ask for backdated tax returns and charge penalties and interest.
This can become a bigger issue where several years have passed.
How much could the penalty be?
HMRC penalties for failing to notify are based on the potential lost revenue. In simple terms, that means the tax that was unpaid because HMRC was not told on time.
Penalties can be up to:
- 30% for a non-deliberate failure
- 70% for a deliberate failure
- 100% for a deliberate and concealed failure
A genuine reasonable excuse may help, such as serious illness or bereavement, but simply not knowing the rules is unlikely to be enough.
What if you come forward voluntarily?
Coming forward before HMRC contacts you is normally better than waiting.
A voluntary disclosure can be made through HMRC’s digital disclosure service. HMRC will then issue reference numbers, and the disclosure usually needs to be completed within 90 days of HMRC acknowledging it.
The tax normally needs to be paid at the same time.
The sooner the position is corrected, the easier it usually is to manage.
Backdated tax returns can add up
If HMRC decides you should have registered in earlier years, they may require Self Assessment tax returns for each year that should have been filed.
Each late return can carry automatic penalties, including:
- an initial £100 late filing penalty
- daily penalties after three months
- further penalties at six and twelve months
- interest and penalties on unpaid tax
If several years are involved, the penalties can build quickly.
Making Tax Digital could also matter
Late registration is no longer just about an annual tax return.
Making Tax Digital for Income Tax is changing the compliance landscape for self-employed individuals.
Self-employed individuals with gross income above £50,000 are brought into the regime first, with the threshold reducing to £30,000 from April 2027 and £20,000 from April 2028.
If someone registers late and their income was above the relevant threshold, HMRC may expect them to have complied with the digital record keeping and quarterly update requirements from when the obligation first applied.
That means a late registration issue could also become a Making Tax Digital issue.
Do not forget VAT
Late registration is not only an income tax problem.
If your taxable turnover goes over the VAT registration threshold, currently £90,000 in a rolling 12-month period, you may also need to register for VAT.
If VAT registration is late, HMRC can require VAT to be paid on past sales, even if you did not charge VAT to your customers at the time.
That can create a painful cashflow problem.
The key point
If you have started self-employment and have not yet registered, do not ignore it.
The sooner the position is reviewed, the better.
At williams lester accountants, we help business owners get registered, understand what needs filing, and deal with HMRC before small admin issues become expensive tax problems.