What Happens After You Register as Self-Employed?

Short answer

Registering is the start, not the finish. After registering, you will receive a Unique Taxpayer Reference (UTR) from HMRC. You then need to keep records, understand your Self Assessment obligations, set money aside for tax, and build basic admin habits. The quality of your first-year records directly affects how straightforward your first tax return will be.

Registration is not the finish line

Many new sole traders register with HMRC and then feel that the main admin task is done. Registration is an important step, but it opens a process rather than completing one. After registering, HMRC sets you up for Self Assessment and you become responsible for reporting your income and expenses each tax year. Good habits established early make the whole system easier to manage.

What HMRC may send you

After registering, HMRC will typically send you a letter by post containing your UTR (Unique Taxpayer Reference). The letter is usually addressed to your registered home address. Keep this letter safely - the UTR is your key reference for all HMRC Self Assessment dealings. HMRC may also send information about activating your online Self Assessment account.

What a UTR is

A UTR (Unique Taxpayer Reference) is a 10-digit number that HMRC uses to identify you for Self Assessment. You will need it to file your tax return and to communicate with HMRC about your Self Assessment account. You can begin invoicing and running your business before your UTR arrives - receiving the UTR is an administrative step, not a condition on trading.

Start keeping records immediately

From the day you register (and ideally from the day you start trading), keep clear records of your income and expenses. HMRC expects self-employed people to keep records that support the figures in their Self Assessment return.

• Record all income: who paid you, when, how much
• Record all expenses: what for, when paid, supplier
• Keep receipts and evidence for every expense you may wish to claim
• HMRC guidance recommends keeping records for at least 5 years after the filing deadline for the relevant tax year

Set up invoices and payment tracking

If you send invoices to clients, set up a simple system for tracking what you have invoiced and what has been paid. A spreadsheet works well for many early-stage sole traders. What matters is that you can clearly identify total income received at the end of the year. A basic invoice should include your name, the date, what was supplied, and the amount.

Understand your first tax return

Your Self Assessment tax return covers the tax year from 6 April to 5 April. If you registered and started trading within a tax year, your first return covers income and expenses from when you started to the end of that tax year.

• Online filing deadline: 31 January following the end of the tax year
• The tax owed is also due by 31 January
• You file online through HMRC's Self Assessment service using your UTR and online account

Save for tax

As a sole trader, no tax is automatically deducted from your income as it would be through PAYE. You are responsible for setting money aside so you can pay your tax bill when it falls due. A common approach is to set aside a proportion of income each time you receive a payment. The right proportion depends on your income level and allowable expenses - a qualified accountant can advise on an appropriate figure for your specific situation.

Review whether you need tools or advice

Many new sole traders manage their records with a spreadsheet, particularly in year one. Accounting software can make record-keeping and tax return preparation easier as income grows. Whether you need an accountant depends on the complexity of your situation. Simple sole trader businesses with straightforward income and expenses are often manageable, but an accountant can help with tax return preparation, advice on allowable expenses, and planning as your business develops.

When to get professional advice

If your income is growing quickly, you have complex expenses to consider, you are unsure about specific expense claims, or you want to understand your full tax position, speaking to a qualified accountant is the appropriate next step. The free tools on this site are starting points, not substitutes for individual advice.