When Do I Need To Register My Business With HMRC? Self Assessment, VAT, PAYE And Company Deadlines
If you’re asking when do i need to register my business with HMRC, the timing depends on what you’re doing: starting self-employment, forming a limited company, hiring staff, or crossing VAT thresholds.
Different business setups trigger different HMRC registrations, whether that’s Self Assessment, Corporation Tax, PAYE or VAT.
You generally need to register with HMRC when you have untaxed business income to report, when a company becomes active for Corporation Tax, before you pay employees, or when your VAT-taxable turnover passes the threshold or is expected to do so within 30 days.
Because the deadlines don’t all line up, sorting registration early reduces the risk of penalties and last-minute delays.
When Do I Need To Register My Business With HMRC?
If you trade as a sole trader, you usually register for Self Assessment in the tax year you start trading and by the relevant deadline after that tax year ends. If you operate through a limited company, you register the company for Corporation Tax when it becomes active.
If you pay staff, you register as an employer before the first payday. If taxable turnover exceeds the VAT threshold, VAT registration becomes compulsory.
What Really Determines The Timing?
HMRC doesn’t use one universal “business registration date”. It uses specific triggers tied to tax at source and tax not at source.
The practical question is: which HMRC service applies to your activity right now, Self Assessment, Corporation Tax, PAYE, or VAT, and what is the earliest point HMRC expects you to notify them after that trigger happens?
What Usually Changes The Answer?
- You start selling goods or services for profit (including freelancing and most side hustles).
- You incorporate and then begin business activity as a company director.
- You hire or pay someone (employee or certain subcontractor arrangements).
- Your VAT-taxable turnover grows beyond the compulsory registration point.
What Registering With HMRC Means In Practice?
Registering is not one form; it’s selecting the correct HMRC process and getting the right identifiers so you can file, pay, and keep compliant records.
Here’s how it normally breaks down.
| What you’re doing | What you register for | What you receive | What it’s for |
|---|---|---|---|
| Sole trader or untaxed income | Self Assessment | UTR (Unique Taxpayer Reference) | Annual tax return, Income Tax, National Insurance |
| Limited company becomes active | Corporation Tax | HMRC account access for CT | Company tax returns and payments |
| Paying staff | PAYE as an employer | Employer PAYE reference | Payroll, RTI submissions like FPS |
| Exceeding VAT threshold | VAT | VAT registration number | VAT charging, VAT Returns, Making Tax Digital |
In practice, confusion often comes from mixing up Companies House registration (creating the company) with HMRC registration (tax services). They’re connected, but not the same thing.
Similar timing issues crop up with personal income too, including situations like Alan Perkins state pension tax where PAYE and pension deductions don’t match what people expect.
Do You Need To Register As Self Employed Or Can You Wait?
If you’re trading as an individual, the key decision is whether you need to report income through Self Assessment and pay tax/National Insurance outside PAYE.
A common pattern is that people “test the waters” with a few invoices, then forget that HMRC looks at the tax year and reporting requirements, not the moment you feel like you have a “real” business.
You’ll usually need Self Assessment if:
- You work for yourself as a sole trader or freelancer and earn more than the £1,000 trading allowance from trading income.
- You have untaxed income that HMRC expects you to declare through a tax return (for example, some types of rental or investment situations).
- You need to claim certain reliefs or handle tax that isn’t fully collected through PAYE.
If you’ve got other untaxed income alongside trading, keep the rules separate, for example, Do I have to notify HMRC of savings interest where interest is paid gross.
You may not need to register yet if:
- Your total trading income for the tax year is £1,000 or less, and nothing else requires a return
- You made a one-off sale that is not trading activity (context matters)
Example: A full-time employed graphic designer starts taking weekend logo jobs. In the first year, receipts are £700. They track invoices and expenses, but don’t register for Self Assessment because trading income stays within the trading allowance. The next year, work grows to £3,500, and registration becomes sensible well before deadlines.
When do you have to tell HMRC about Self Assessment?
For many first-time traders, this is the deadline that catches them out.
The Main Self Assessment Timing Rule
If you need to submit a Self Assessment tax return for the previous tax year and it’s your first time (or you didn’t file in a recent year), you generally must tell HMRC by 5 October after the end of that tax year.
That’s separate from filing and paying deadlines, which are later (and differ for online vs paper filing). Registering earlier avoids delays in getting a UTR or activating an account.
Cashflow can also be affected by how HMRC reconciles payments, including whether Do HMRC automatically refund overpaid tax after year end or only once your record is updated.
Example: A gardener begins trading in July and earns over £1,000 before the tax year ends. They keep records but don’t register until December. They can still register, but it creates stress because the Self Assessment setup and UTR letter timing can become the bottleneck.
When must a limited company register for Corporation Tax?
A limited company must register for Corporation Tax when it becomes active and is within the charge to Corporation Tax. What matters is the moment the company starts business activity, not the incorporation date alone.
How HMRC view company activity?
Business activity isn’t limited to sales. HMRC may treat a company as active once it starts doing things like:
- Buying stock or materials to sell.
- Marketing services and taking paid work.
- Charging customers, issuing invoices, or receiving trading income.
- Employing someone or paying the director in a payroll-like way.
What counts as starting to trade?
| Scenario | Often treated as trading activity | Why it matters |
|---|---|---|
| Company opens a bank account and deposits share capital only | Usually no | Admin setup alone isn’t trading |
| Company buys a laptop and software to deliver client work | Often yes | Incurs costs for business purposes |
| Company signs a paid contract and issues the first invoice | Yes | Clear start of trading |
| Company holds only investments and earns interest | Maybe | Can be non-trading activity but still “active” for CT |
When reviewing real-world setups, the most common misstep is assuming the company is “dormant” because there are no sales yet, while business costs and activity have already started.
When do you need to register for VAT?
VAT registration becomes compulsory when VAT-taxable turnover crosses the threshold in a rolling period, or when you expect to exceed it soon. As of 2026, the VAT registration threshold is £90,000 of VAT-taxable turnover.
VAT registration triggers you should recognise
VAT can become compulsory in two common ways:
| Trigger | What HMRC looks at | Practical meaning |
|---|---|---|
| Past turnover test | More than £90,000 VAT-taxable turnover in any rolling 12 months | You register because you’ve already crossed it |
| Future turnover test | You expect to exceed £90,000 in the next 30 days alone | You register because a large contract is about to land |
Example: A caterer is at £82,000 rolling turnover, then signs a corporate contract worth £15,000 for next month. Even if the year-end accounts are months away, the 30-day expectation test can make VAT registration urgent.
Voluntary VAT registration can make sense if:
- You sell mostly to VAT-registered businesses that can reclaim VAT.
- You have significant VAT on costs (equipment, materials, professional services).
- Your pricing strategy can handle charging VAT without losing competitiveness.
When do you need to register as an employer for PAYE?
You must register as an employer before the first payday so you can get an employer PAYE reference. You generally cannot register too far in advance, so plan around your intended pay date.
Signs You’re An Employer In HMRC Terms
- You’re paying an employee a wage or salary.
- You’re running payroll and making deductions for Income Tax and National Insurance.
- You’ll need to submit Real Time Information, such as an FPS, on or before payday.
It helps to choose payroll software early, because RTI reporting and payslip requirements are simpler when they’re set up from day one.
How To Register With HMRC Without Missing A Deadline?
- Decide your structure: sole trader, partnership, or limited company.
- Create or confirm your Government Gateway credentials.
- Register for Self Assessment if you’ll need to file a return for business income.
- If you’re a limited company, add Corporation Tax to your business tax account once active.
- Register for PAYE before your first payday if you’ll employ staff.
- Track VAT-taxable turnover monthly against the £90,000 threshold and the 30-day expectation test.
- Set up record-keeping: invoices, receipts, bank feeds, and expense categories.
What Causes Late Registration And Avoidable Penalties?
Late registration is usually down to missed triggers and misunderstood deadlines, rather than anything deliberate.
Common Mistakes That Keep Coming Up
- Waiting for a “steady month” before registering, then missing the 5 October Self Assessment notification deadline.
- Assuming incorporation automatically registers the company for all taxes.
- Treating VAT as an “end of year” decision instead of a rolling 12-month test.
- Paying someone before PAYE registration is in place, then scrambling to correct RTI submissions.
Simple Habits That Reduce Risk
- Keep a single “tax admin” folder with your NI number, Companies House info, bank details, and ID documents.
- Track income by tax year and by rolling 12-month turnover (they’re different).
- Put three dates in your calendar: end of tax year, 5 October, and filing/payment deadlines.
Record Keeping That Makes HMRC Registration Easier
The fastest registrations happen when your basic facts are consistent across documents and accounts.
Have This To Hand
- Trading start date and business address.
- Business bank account details (even if it’s a separate account for a sole trader).
- Main business activity description and SIC code for companies.
- Estimates of turnover and whether you’re close to VAT thresholds.
In practice, clean records also make it easier to correct errors, amend returns, or answer HMRC queries without panic.
When Do I Need To Register My Business With HMRC If I Start As A Side Hustle?
If your side hustle produces more than £1,000 in trading income in a tax year, registration for Self Assessment often becomes relevant.
If it stays under the trading allowance, you may not need to register, but you should still keep records in case income rises, you add new income sources, or you later need to prove figures for a mortgage or an accountant review.
What People Talk About This Online?
— Small Business Commissioner UK (@SB_Commissioner) January 16, 2026
about to hit the 90K threshold for collecting VAT as a clothing brand (UK)…
byu/Apprehensive_Dog8285 inecommerce
Final Summary
Start by identifying which HMRC “lane” you’re in: Self Assessment for sole traders and untaxed income, Corporation Tax for active limited companies, PAYE before paying employees, and VAT if taxable turnover crosses £90,000 or will do so within 30 days.
Put the key dates in your calendar, track turnover monthly, and keep invoices and receipts from day one so registration is quick and accurate.
FAQ
Do I need to register with HMRC before my first invoice?
Not always. Many people issue an invoice and register later, as long as they register in time for the relevant tax obligations. The safer approach is to register once you can see you’ll exceed the £1,000 trading allowance or will definitely need Self Assessment for that tax year.
Can I invoice clients without a UTR?
Yes, you can invoice without a UTR. A UTR is mainly for filing your Self Assessment tax return and managing your HMRC account. Some clients or agencies may ask for it as part of onboarding, but it is not a legal requirement for issuing an invoice.
What if I’m employed and freelancing on the side?
Employment income is usually taxed through PAYE, but freelance income is typically not. If your freelance trading income exceeds the £1,000 trading allowance or you otherwise need Self Assessment, you register and report both income streams correctly through your return.
If I made a loss, do I still need to register?
Possibly. Registration is driven by whether you need to complete a tax return, not whether you made a profit. Losses can still be relevant for reporting and, in some cases, reliefs. Keep records and register if Self Assessment is required for your circumstances.
When exactly is the Self Assessment registration deadline?
If you need to file Self Assessment for the previous tax year and it’s your first time (or you didn’t file in a recent year), you generally must notify HMRC by 5 October after that tax year ends. Filing and payment deadlines come later and should be diarised separately.
Does forming a limited company automatically register me for Corporation Tax?
No. Incorporation creates the company at Companies House, but you still need to ensure Corporation Tax is set up once the company becomes active. HMRC expects the company to be registered for Corporation Tax within the required time after it starts business activity.
When do I have to register for VAT if I cross the threshold?
If your VAT-taxable turnover exceeds £90,000 in a rolling 12-month period, VAT registration becomes compulsory. You also need to register if you expect to exceed £90,000 in the next 30 days alone. Monitoring monthly turnover prevents accidental late registration.
I hired someone for a short job. Do I need PAYE?
It depends on whether they are an employee and how they’re paid. If you’re paying wages and running payroll, PAYE registration is typically needed before the first payday. Employment status can be nuanced, so many businesses check HMRC employment status guidance or use professional payroll support.
What happens if I register late?
Late registration can lead to penalties and interest depending on the tax involved and how late it is. The bigger issue is often operational: delayed UTRs, delayed VAT numbers, and messy corrections. Registering early and keeping clean records is the easiest way to reduce exposure.
Author note
Written from hands-on experience reviewing small-business registrations, payroll setups, and VAT trigger points, focusing on practical timing and clean records. This is general information using HMRC process terms, not legal or personalised tax advice; confirm your position with HMRC guidance or a qualified adviser.
