Good bookkeeping is the difference between a self-employed tax return that takes an afternoon and one that eats a weekend, and from 6 April 2026 it matters more than ever: Making Tax Digital for Income Tax now forces many sole traders to keep digital records and file quarterly. This guide shows you exactly what to record, which accounting method to use, how to set up a simple system, and how to get ready for the new rules.
It is written for UK sole traders, freelancers and solo contractors who do their own books, or want to understand what their accountant needs. Every figure here was checked against gov.uk on 14 October 2026.
What is self-employed bookkeeping?
Self-employed bookkeeping is the day-to-day record-keeping of every penny your business earns and spends, so you can work out your taxable profit, file an accurate Self Assessment return, and prove your figures if HMRC ever asks. For a sole trader it is simpler than company accounting: there is no payroll for yourself and no Companies House filing, just a clean record of income and allowable expenses.
Done well, bookkeeping is not just a compliance chore. It tells you whether you are actually making money, how much tax to set aside, and when you are approaching the VAT or Making Tax Digital thresholds. If you are only now setting up, start with our guide to registering as self-employed with HMRC, then come back here for the records side.
Do you need to register and keep records?
You must register for Self Assessment and keep business records once your gross self-employed income (before expenses) exceeds the £1,000 trading allowance in a tax year. Below £1,000 you can usually rely on the allowance and keep nothing formal; above it, you are a sole trader in HMRC's eyes and record-keeping becomes a legal requirement, not an option.
The trading allowance is a flat £1,000 deduction you can claim instead of your actual expenses, which suits low-cost businesses. If your expenses are higher than £1,000, you deduct the real figures instead and keep the paperwork to back them up. Our list of allowable expenses for sole traders shows what you can claim.
What records must a sole trader keep?
A sole trader must keep a complete record of all business income and all allowable business expenses, plus anything needed to support a Self Assessment entry. HMRC does not prescribe a format, so a spreadsheet or app is fine, as long as the figures are accurate, complete and backed by evidence such as invoices, receipts and bank statements.
| Record type | Examples to keep |
|---|---|
| Sales and income | Invoices you issue, till rolls, PayPal, Stripe and marketplace statements |
| Business expenses | Receipts, supplier bills, mileage logs, home-office calculations |
| Bank and finance | Business bank and card statements, loan and finance agreements |
| VAT (if registered) | VAT invoices issued and received, your VAT account |
| Employees (if any) | Payroll records, if you take anyone on |
| Other taxable income | Grants, interest, and anything else that is taxable |
Keeping receipts digital saves space and is the direction HMRC is pushing: see how to digitise receipts for HMRC. For the wider record-keeping picture, including limited companies, our small business bookkeeping basics guide covers what every business must record.
How long must you keep self-employed records?
You must keep your self-employed records for at least five years after the 31 January Self Assessment deadline of the relevant tax year. For the 2026/27 return filed by 31 January 2028, that means keeping your records until at least 31 January 2033. HMRC can check them at any point in that window. Our guide to how long to keep business records covers the exceptions.
Cash basis or traditional accounting: which should you use?
From the 2024/25 tax year the cash basis is the default for sole traders: you record income when money actually reaches you and expenses when you actually pay them. Traditional accruals accounting, which records income when invoiced and expenses when incurred, is now the option you must actively elect for on your tax return. For most freelancers the cash basis is simpler and better for cash flow.
| Feature | Cash basis (default) | Traditional (accruals) |
|---|---|---|
| Income counted when | Money is received | Invoice is raised |
| Expenses counted when | You pay them | You incur them |
| Best for | Most sole traders and freelancers | Stock-heavy or larger businesses |
| Turnover limit | None (scrapped from 2024/25) | None |
| How to choose it | Automatic, no action needed | Tick the box on your return |
The practical difference matters at the year end. Under the cash basis, an invoice you raise on 25 March but are paid for on 10 April falls into the next tax year, because that is when the money arrived. Under accruals it would land in the earlier year. Our full comparison of cash basis versus accruals for sole traders works through more examples.
How do you set up a bookkeeping system?
Setting up self-employed bookkeeping takes four steps: separate your business money, pick a method of recording it, record every transaction as it happens, and reconcile against your bank regularly. You do not need expensive software to start, but from April 2026 anyone inside Making Tax Digital must use compatible digital tools rather than a paper cash book.
- Separate your finances. A sole trader is not legally required to have a business bank account, but a dedicated account (or at least a separate card) makes bookkeeping far faster and keeps personal spending out of your figures.
- Choose how you record. A spreadsheet works when you are small; MTD-compatible software (or a bridging app) becomes necessary once you are in Making Tax Digital. Pick something you will actually keep up with.
- Record as you go. Log income when it lands and expenses when you pay them, attach the receipt or invoice, and categorise it. A ten-minute weekly habit beats a year-end scramble.
- Reconcile monthly. Match your records to your business bank statement every month so errors surface in weeks, not at the filing deadline.
As you record income, set tax aside at the same time so the bill is never a shock. Our guide to how much a sole trader should put aside for tax gives a rule of thumb, and you can sense-check it with our self-employed tax calculator for 2026/27. When you bill clients, keep the paperwork consistent using our guide to invoicing as a sole trader.
Worked example: a freelancer's cash-basis year
Say a freelance designer receives £48,000 into their business account during 2026/27 and pays £8,000 of allowable expenses (software, equipment, a share of home costs and travel). Under the cash basis their taxable profit is simply £48,000 minus £8,000, which is £40,000. That profit figure drives both the income tax and the Class 4 National Insurance on their return.
On a £40,000 profit the Class 4 National Insurance for 2026/27 is 6% on the slice above £12,570, which is 6% of £27,430, or about £1,645, on top of income tax. Keeping the books current all year means that number is known long before the 31 January deadline, not discovered at the last minute. Our guide to self-employed National Insurance for 2026/27 explains the Class 2 and Class 4 position in full.
How does Making Tax Digital change self-employed bookkeeping?
Making Tax Digital (MTD) for Income Tax makes digital record-keeping and quarterly reporting compulsory for sole traders and landlords above an income threshold. It started on 6 April 2026 for those with qualifying income over £50,000, and the threshold steps down over the following two years. Qualifying income is your gross turnover before expenses, with self-employment and property income added together.
| Qualifying income (gross, before expenses) | MTD for Income Tax applies from |
|---|---|
| Over £50,000 | 6 April 2026 |
| Over £30,000 | 6 April 2027 |
| Over £20,000 | 6 April 2028 |
If you are in MTD you must keep digital records and send HMRC a cumulative update every quarter through compatible software, then a Final Declaration in place of the old Self Assessment return. The practical upshot is that shoebox-of-receipts bookkeeping no longer works: you need a digital system from the start of your first MTD tax year. There are no penalties for missing a quarterly update in the first year you join, but late-payment penalties still apply, so do not treat it as optional. Check your own position on the gov.uk eligibility checker.
Common self-employed bookkeeping mistakes
- Mixing business and personal spending. It makes every figure harder to prove and slows down your return.
- Leaving it to January. A year's worth of transactions reconstructed from memory is where errors and missed expenses creep in.
- Binning receipts. No evidence means a disallowed expense if HMRC asks. Photograph or scan everything.
- Forgetting to set tax aside. The profit in your account is not all yours; income tax and Class 4 NIC are still to come.
- Ignoring the MTD threshold. Qualifying income is gross, not profit, so you can be caught sooner than you expect.
If bookkeeping is eating time you would rather spend earning, that is exactly what we do. Zmartly is a CIMA-regulated firm and our qualified accountants keep the books, file the returns and handle Making Tax Digital for sole traders and freelancers on a fixed monthly fee. See our bookkeeping service or book a free call and we will set your system up properly from the start.
Frequently asked questions
Do I need an accountant to do my own bookkeeping?
No. A sole trader can legally keep their own books and file their own Self Assessment return, and many do with a spreadsheet or simple app. An accountant becomes worthwhile when your time is better spent earning, your affairs get more complex, or you move into Making Tax Digital and want the quarterly filing handled for you.
What is the best software for self-employed bookkeeping?
The best software is one that is recognised by HMRC for Making Tax Digital and that you will actually keep up to date. For sole traders inside MTD you must use compatible software or a bridging tool; below the threshold a spreadsheet is still allowed, but moving to software early makes the eventual switch to MTD far smoother.
Can I use the cash basis if I am self-employed?
Yes, and for most sole traders it is now automatic. Since the 2024/25 tax year the cash basis is the default method, so you record income when you are paid and expenses when you pay them unless you actively elect for traditional accruals accounting on your tax return. The old turnover limits were scrapped.
How long do I keep my bookkeeping records as a sole trader?
At least five years after the 31 January Self Assessment deadline for that tax year. So records for the 2026/27 return, filed by 31 January 2028, must be kept until at least 31 January 2033. HMRC can open a check within that period and ask to see the evidence behind your figures.
