Sole Trader Bookkeeping: The Records You Must Keep (UK)

Short answer: As a UK sole trader, you must keep records of all your business income and expenses so you can complete an accurate Self Assessment tax return. That means keeping copies of invoices you issue, receipts for what you buy, bank statements, and mileage logs. HMRC requires you to keep these records for at least 5 years after the 31 January submission deadline of the relevant tax year. You do not have to use accounting software, but you must keep the records complete and accurate.

Bookkeeping sounds intimidating, but for most sole traders it is just organised record-keeping: knowing what came in, what went out, and being able to prove it. Do it a little at a time and the annual tax return becomes a quick job rather than a crisis.

What records must a sole trader keep?

HMRC does not prescribe a specific format, but it expects a complete picture of your business finances. At minimum, keep records of:

• All sales and income: copies of invoices you issue and proof of what you were paid
• All business expenses: receipts and invoices for what you buy for the business
• Bank and card statements for business transactions
• Mileage and travel records if you claim vehicle costs
• VAT records if you are VAT registered
• Records of any personal money you put into or take out of the business
• Grants or support payments received (these can be taxable)

According to GOV.UK (“Business records if you’re self-employed”), you must keep records of all sales and income, all business expenses, VAT records if registered, PAYE records if you employ people, and your personal income.

How long do I have to keep records as a sole trader?

You must keep your sole trader records for at least 5 years after the 31 January submission deadline of the relevant tax year, per GOV.UK.

Situation	How long to keep records
Standard case	At least 5 years after the 31 January submission deadline for that tax year
Example: 2025/26 return filed by 31 January 2027	Keep until at least the end of January 2032
Return filed more than 4 years late	Keep records for 15 months after you send the return
VAT registered	Generally keep VAT records for 6 years (verify on GOV.UK)

HMRC can check your records at any point in these windows to make sure you paid the right tax. Missing records can mean HMRC estimates your income, and penalties can apply for failing to keep adequate records.

What is the difference between income and expenses?

Good bookkeeping separates money in from money out.

• Income (turnover): everything your business earns, mainly from sales and services, before any deductions.
• Allowable expenses: costs incurred wholly and exclusively for the business, which you can deduct to reduce your taxable profit. Common examples include stock, materials, business travel, some use-of-home costs, professional fees, insurance and marketing.
• Profit: income minus allowable expenses. This is what you are taxed on through Self Assessment.

Not every cost is an allowable expense, and private costs are not deductible. When in doubt, check GOV.UK’s “Expenses if you’re self-employed” guidance or ask an accountant.

Cash basis or traditional accounting: which should I use?

Sole traders can usually choose how they record income and expenses.

Method	How it works	Best for
Cash basis	Record income when money is actually received and expenses when actually paid	Most small sole traders; simpler, and you are not taxed on money you have not yet received
Traditional (accruals) accounting	Record income and expenses when they are invoiced or incurred, regardless of when cash moves	Larger or more complex businesses, or where you need a fuller financial picture

Cash basis is the default for many self-employed people and keeps things simple. Whichever you choose, be consistent and check the current GOV.UK rules, as eligibility and defaults have changed over time.

What does a simple bookkeeping routine look like?

You do not need a finance degree. A light, regular habit beats an annual marathon.

Weekly (10 minutes):

• Capture every receipt as you get it
• Save copies of invoices you have sent and note which are paid
• Log any business mileage

Monthly (30 minutes):

• Reconcile your records against your bank statement
• Chase any unpaid invoices
• Set aside a percentage of profit for tax

Yearly:

• Total income and expenses
• Complete and file your Self Assessment return
• Archive the year’s records for the 5-year retention period

Do I need accounting software as a sole trader?

Not necessarily. HMRC allows records to be kept on paper, in a spreadsheet or in software, as long as they are accurate and complete. However, two things are pushing sole traders towards digital records:

1. Making Tax Digital for Income Tax: from 6 April 2026, sole traders and landlords with qualifying income over £50,000 must keep digital records and send quarterly updates using compatible software. The threshold drops to £30,000 from April 2027 and £20,000 from April 2028. Check “Making Tax Digital for Income Tax” on GOV.UK to see when it applies to you.
2. Convenience: capturing receipts and invoices digitally as they happen prevents the year-end scramble.

How Keel helps with sole trader record-keeping

Keel: Invoice Maker & Receipts by Ilura Technology is a private, on-device app built for the self-employed. You can create invoices, capture receipts and log business trips, and everything is stored encrypted on your iPhone, with no bank connection, no cloud and no account. Its App Store privacy label reads “Data Not Collected”, so your books stay on your device.

For a sole trader, that covers the core of day-to-day bookkeeping: a copy of every invoice you issue, a photo of every receipt, and a log of business trips, all in one private place you can hand to an accountant.

Two honest caveats for UK users. First, Keel is currently US-centric, so its built-in mileage rate is the IRS rate, not the HMRC rate; treat its trip feature as a private mileage log and apply the correct HMRC rate at tax time. Second, because Keel keeps data only on your device, remember to back up your iPhone so your records survive a lost or replaced phone. Keel is a record-keeping tool, not a substitute for filing your return or for MTD-compatible software if you are within scope.

Frequently asked questions

How long do sole traders have to keep records in the UK? At least 5 years after the 31 January submission deadline of the relevant tax year, according to GOV.UK. If you file more than 4 years late, keep records for 15 months after you send the return.

Do I legally need accounting software? No. You can keep records on paper, in a spreadsheet or in an app, provided they are accurate and complete. But Making Tax Digital for Income Tax will require digital records for sole traders above certain income thresholds from April 2026 onwards.

What expenses can I claim as a sole trader? Costs incurred wholly and exclusively for the business, such as stock, materials, business travel, professional fees and some use-of-home costs. Private costs are not allowable. See GOV.UK “Expenses if you’re self-employed”.

What happens if I lose a receipt? Reconstruct what you can from bank or card statements and note the details. HMRC expects reasonable records; persistent gaps can lead to disallowed expenses or penalties, so capture receipts as you go.

Is bookkeeping the same as doing my tax return? No. Bookkeeping is the ongoing task of recording income and expenses. Your Self Assessment tax return is the annual submission that uses those records.

The bottom line

Sole trader bookkeeping in the UK comes down to three things: record all your income, keep receipts for all your business costs, and store everything for at least 5 years. Build a light weekly habit and the annual Self Assessment return stops being scary. A private, on-device app like Keel can hold your invoices, receipts and trip logs in one place on your iPhone. Always confirm current rules on GOV.UK, and bring in an accountant when it matters.

Try Keel on the App Store: https://apps.apple.com/us/app/keel-invoice-maker-receipts/id6786659713 (Free: 3 invoices/month plus unlimited receipts; Pro is roughly the £ equivalent of $7.99/month or $59.99/year, see the App Store for local pricing).

This article is general information, not tax advice. Consult a qualified accountant or tax adviser.