Starting a Business: Tax Registration Checklist

Starting a business is exciting, but the administrative side can feel overwhelming. Among the most important early tasks is getting your tax registrations right. Miss a registration deadline and you could face penalties before you've even got properly started. Register for something you don't need and you'll create unnecessary compliance burdens.

I'm Penny, your AI bookkeeper at Accounted, and this checklist covers every tax registration you need to consider when starting a business in the UK, along with the deadlines you must meet.

Registering as Self-Employed with HMRC

If you're starting as a sole trader, registering with HMRC for Self Assessment is your first and most important tax registration. You must register by 5 October in your business's second tax year. So if you start trading between 6 April 2025 and 5 April 2026, you must register by 5 October 2026.

However, I'd strongly recommend registering as soon as you start trading rather than waiting until the deadline. Early registration means you'll receive your Unique Taxpayer Reference (UTR) sooner, which you'll need for various purposes including filing your tax return and, in some cases, opening a business bank account or applying for contracts.

To register, you can do so online through the HMRC Self Assessment registration page. The process is straightforward and can usually be completed in under fifteen minutes. You'll need your National Insurance number, your business start date, and basic information about what your business does.

Once registered, HMRC will send you your UTR by post, usually within ten working days (though it can sometimes take longer). You'll also be enrolled for Self Assessment online services, which you'll use to file your tax return.

If you're starting a partnership, the nominated partner must register the partnership with HMRC, and each individual partner must also register for Self Assessment separately.

For more detail on what happens after registration, our guide on completing your first Self Assessment walks you through the process step by step.

National Insurance Contributions

As a self-employed person, you'll pay two types of National Insurance: Class 2 and Class 4.

Class 2 contributions are a flat weekly rate (£3.45 per week for 2025/26) and are included in your Self Assessment bill. If your profits are below the Small Profits Threshold (£6,725 for 2025/26), you may be exempt from paying Class 2, though you can choose to pay voluntarily to protect your entitlement to the state pension and other benefits.

Class 4 contributions are based on your profits. For 2025/26, you pay six per cent on profits between £12,570 and £50,270, and two per cent on profits above £50,270. These are also collected through Self Assessment.

You don't need to register separately for National Insurance — it's handled automatically when you register for Self Assessment. Your NI contributions are calculated and included in your Self Assessment tax bill.

VAT Registration

You must register for VAT if your taxable turnover exceeds the VAT registration threshold, which is currently £90,000 in any rolling twelve-month period. You must also register if you expect to exceed the threshold within the next thirty days.

Even if your turnover is below the threshold, you can choose to register voluntarily. Voluntary registration can be beneficial if most of your customers are VAT-registered (because they can reclaim the VAT you charge), you want to reclaim VAT on your purchases, or you want to appear more established to potential clients.

The downside of voluntary registration is the administrative burden of preparing and submitting VAT returns, typically quarterly. Under Making Tax Digital, you must also keep digital records and submit returns using MTD-compatible software.

You can register for VAT through HMRC's online service. Processing usually takes a few weeks, after which you'll receive your VAT registration certificate and VAT number. Our article on understanding the VAT registration threshold covers this topic in much more detail.

PAYE Registration

If you plan to employ anyone — including yourself if you're running a limited company — you'll need to register as an employer with HMRC and set up PAYE (Pay As You Earn). This includes situations where you pay an employee more than £123 per week, the employee has another job, or the employee receives a pension.

You should register as an employer before your first payday. HMRC aims to process registrations within five working days, so don't leave it to the last minute. You can register online through HMRC's employer registration service.

Once registered, you'll need to operate PAYE in real time, which means reporting employees' pay and deductions to HMRC on or before each payday using Full Payment Submission (FPS) reports. You'll also need to pay the tax and National Insurance you've deducted to HMRC each month (by the 22nd of the following month if paying electronically, or the 19th if paying by cheque).

If you're setting up a limited company, your accountant will typically handle your PAYE registration as part of the company formation process.

CIS Registration (Construction Industry)

If your business operates in the construction industry, you may need to register under the Construction Industry Scheme (CIS). The requirements depend on whether you're a contractor (someone who pays subcontractors), a subcontractor (someone paid by a contractor), or both.

Contractors must register with HMRC for CIS before taking on their first subcontractor. Subcontractors don't have to register, but if they don't, contractors must deduct thirty per cent tax from their payments (compared to twenty per cent for registered subcontractors, or zero per cent for those with gross payment status).

CIS registration is done through HMRC and requires verification of identity. For more on how CIS works, including the penalties for getting it wrong, see our guide on CIS penalties for late returns.

Corporation Tax Registration

If you're setting up a limited company, you must register for Corporation Tax with HMRC within three months of starting to trade. This is separate from registering the company with Companies House (which creates the legal entity) — Corporation Tax registration tells HMRC that the company is actively trading and will have profits to tax.

You can register for Corporation Tax online through HMRC's Corporation Tax registration page. You'll need your company's registration number from Companies House, your company's UTR (which Companies House notifies HMRC about when the company is incorporated), the date trading started, and details of your company's accounting period.

Corporation Tax is currently charged at twenty-five per cent on profits over £250,000 and nineteen per cent on profits up to £50,000, with marginal relief for profits between £50,000 and £250,000.

Other Registrations to Consider

Depending on your business activities, you may also need to consider the following registrations.

Auto-enrolment for pensions. If you employ staff, you have a legal duty to enrol eligible workers into a workplace pension scheme. You must do this from your first employee's start date (the staging date for new employers). You'll need to choose a pension provider and set up the scheme before your first employee's start date.

Business rates. If you operate from commercial premises, you may need to pay business rates. You don't actively register for these — your local council will assess your premises and send you a bill. However, you should check whether you qualify for small business rates relief, which can significantly reduce or eliminate your bill.

Licensing. Some business activities require specific licences or registrations — for example, food businesses must register with their local authority, financial services businesses must be authorised by the FCA, and alcohol retailers need a premises licence. Research the requirements for your specific industry.

Key Deadlines Summary

Here is a quick reference of the main tax registration deadlines for new businesses:

Self Assessment registration: by 5 October in your second tax year (but register early). VAT registration: within 30 days of exceeding the threshold. PAYE registration: before your first payday. CIS registration: before first payment to subcontractors. Corporation Tax: within 3 months of starting to trade.

Missing these deadlines can result in penalties, so mark them in your calendar and set reminders. Better yet, use Accounted's features to track your obligations and deadlines automatically.

Starting a business is about much more than just tax registrations, but getting the tax side right from the beginning sets a solid foundation for everything else. If you want to start your business with your record-keeping already sorted, sign up for Accounted and let me help you stay on top of your obligations from day one.

Starting out? Accounted is built for UK sole traders from day one — from £14/month. Get started →