Running your own business is demanding enough without worrying whether your books are in order or whether HMRC has a problem with your records. This guide covers exactly what sole traders need to do, what records the law requires, what you can claim, and when it makes sense to get an accountant involved.

Why accounting for sole traders matters more than ever

Being a sole trader in the UK means HMRC treats you and your business as one legal entity. Every penny you earn through self-employment must be declared, and the rules around record-keeping are stricter than many people realise. HMRC requires sole traders to keep records of all sales, income, and business expenses for at least five years after the 31 January submission deadline.

Tax obligations for sole traders are also about to change in a significant way. From 6 April 2026, sole traders with total annual income over £50,000 must use Making Tax Digital for Income Tax, meaning digital record-keeping and quarterly reporting to HMRC will become mandatory. Getting your accounting sorted now puts you ahead of that deadline rather than scrambling to catch up when it arrives.

Where most sole traders go wrong with their accounting

The most common problem is not ignorance of the rules. It is delay. Most sole traders seek an accountant too late, often after a penalty has already landed or a saving has already been missed. By the time the problem becomes visible, the options for fixing it are narrower and more expensive.

Mixing personal and business money

Using one bank account for both personal spending and business income is one of the most common mistakes sole traders make. It does not take long before you cannot tell what was a business expense and what was a personal purchase. Opening a separate business bank account takes about 15 minutes and saves hours of untangling later.

Not keeping records in real time

Leaving receipts in a drawer or a carrier bag and dealing with them once a year before the deadline is a recipe for missed deductions and stressful filing. HMRC can investigate your records at any point, and you are required to keep them for at least five years after submission. A simple weekly habit of logging income and expenses takes around 30 minutes and prevents the annual panic entirely.

What to do as a sole trader (step by step)

Getting your accounting in order as a sole trader does not require specialist knowledge. It requires consistency. The steps below cover the legal minimum and give you a foundation that will hold up whether you do your own books or hand them to an accountant.

1. Register with HMRC as self-employed and set up a Self Assessment account online. You must register by 5 October in the second year of trading. Once registered, HMRC will send you a Unique Taxpayer Reference (UTR) which you will need for all future tax filings.
2. Open a dedicated business bank account and log every transaction as it happens. Record all income received, every business expense paid, and keep receipts or digital copies for each one. Under cash basis (the current default), you record money when it actually moves, not when an invoice is raised.
3. File your Self Assessment tax return by 31 January each year for the previous tax year (6 April to 5 April). Your tax bill covers Income Tax on your profits and Class 4 National Insurance. If your profits exceed £12,570, you will also owe Class 2 NICs. Pay any tax owed by 31 January to avoid late payment penalties.

If your turnover crosses the VAT registration threshold (currently £90,000), you must register for VAT and file quarterly VAT returns. If you work in the construction industry, CIS deductions and monthly returns will also apply. These add complexity and are worth discussing with an accountant before you reach the threshold rather than after.

Costs and what to expect

The honest answer on cost is that doing your own books is cheap upfront and potentially expensive later. An accountant who knows what they are doing will typically save more than their fee through correctly claimed expenses, better tax planning, and avoiding penalties. At STZ Accounting, the sole trader package is priced at £150 plus VAT per month and covers invoicing, bookkeeping, bank reconciliation, VAT returns, annual accounts, and your personal Self Assessment. There are no variable costs and no bills that arrive without warning.

How to get started today

If your records are already behind, the priority is to get them in order before the next filing deadline rather than wait for a better moment. A 20-minute conversation is usually enough to assess where you are and what needs to happen first. There is no obligation and no sales pitch.

• Gather your bank statements and any receipts from the current tax year and make a note of what you think your total turnover has been. You do not need everything perfect before speaking to an accountant.
• Book a free introductory call with David at STZ Accounting to go through your situation, understand what your obligations are, and get a fixed-price quote for any ongoing work.