How to Do Your Own Bookkeeping as a UK Sole Trader (2026 Guide)

You don't need to hire a bookkeeper to run a sole trader business in the UK. If you're a plumber, electrician, builder, gardener, or any other self-employed tradesperson earning under £50k, you can manage your own books with a simple system — a spreadsheet or a Notion template will do the job.

HMRC doesn't care how you keep records. They care that your records are accurate, complete, and available for at least 5 years after the 31 January Self Assessment deadline.

This guide explains what records you must keep, how to structure your bookkeeping, when to use simplified expenses, and when you might need software or an accountant.

What Records Must You Keep as a UK Sole Trader?

HMRC requires you to keep these records for at least 5 years after the 31 January submission deadline:

1. Sales Records (Income)

• All invoices you send to clients
• Cash sales (if you take cash payments, write them down immediately)
• Bank statements showing payments received
• For CIS subcontractors: monthly CIS statements from contractors

What to record: Date, client name, job description, gross amount, CIS deduction (if applicable), net amount received.

2. Purchase Records (Expenses)

• All receipts for business expenses (materials, tools, fuel, insurance, phone, etc.)
• Bank and credit card statements showing business purchases
• Supplier invoices for materials or equipment

What to record: Date, supplier name, what you bought, category (materials, tools, vehicle, office, etc.), amount.

3. Mileage Log (if claiming vehicle expenses)

If you claim mileage using simplified expenses (45p/mile), keep a log:

• Date of journey
• Starting and ending location
• Business purpose (e.g., "Visit to client site in Bristol")
• Miles driven

If you claim actual vehicle costs (fuel, insurance, repairs, depreciation), keep all receipts and calculate business vs personal use percentage.

4. CIS Records (for subcontractors)

If you work under the Construction Industry Scheme:

• Monthly CIS statements from contractors (showing gross payment, deduction, net payment)
• Contractor verification receipts (when you first register with a new contractor)
• Your own records reconciling CIS statements to your invoices

You'll need these totals at the end of the tax year to claim back any overpaid CIS tax via your Self Assessment return.

5. VAT Records (if VAT registered)

If your turnover exceeds £90,000 (or you voluntarily register), keep:

• VAT invoices issued to customers
• VAT receipts from suppliers
• Digital records in MTD-compatible software

VAT is beyond the scope of this guide — if you're VAT registered, you'll likely need software like Xero, QuickBooks, or FreeAgent.

The Simplest Bookkeeping System for Sole Traders

Here's a basic system that satisfies HMRC requirements without overcomplicating it:

Step 1: Open a separate bank account (recommended)

You don't need a business bank account, but keeping business and personal money separate makes bookkeeping 10x easier. Use your business account for:

• All client payments received
• All business expenses (materials, fuel, tools, subscriptions)
• Paying yourself (transfer to your personal account)

If you can't open a separate account, at least tag or label business transactions in your personal account.

Step 2: Create a simple income & expense tracker

Use a spreadsheet or Notion template with these columns:

Income tab:

• Date
• Client name
• Job description
• Gross amount (before CIS deduction, if applicable)
• CIS deduction (if applicable)
• Net amount received
• Payment method (bank transfer, cash, cheque)

Expenses tab:

• Date
• Supplier/description
• Category (materials, vehicle, tools, insurance, phone, etc.)
• Amount
• VAT (if VAT registered)
• Payment method

Mileage tab (if using simplified expenses):

• Date
• From / To
• Purpose
• Miles
• Rate (45p or 25p)
• Claim amount

Step 3: Record transactions weekly

Don't wait until January to do your books. Set aside 30 minutes every Friday to:

• Enter all invoices sent that week
• Enter all expenses paid
• Log business mileage
• File receipts (physical or scanned) in date order

Weekly bookkeeping takes 30 minutes. Annual bookkeeping takes 3 days of stress in January.

Step 4: Reconcile monthly

At the end of each month, check your tracker against your bank statement:

• Do the income totals match what came into your bank?
• Do the expense totals match what went out?
• Are there any missing transactions?

For CIS subcontractors: reconcile your CIS statements to your income tracker. Make sure the gross, deduction, and net amounts match.

Simplified Expenses: Should You Use Them?

HMRC offers simplified expenses — flat-rate claims that reduce admin. You don't need receipts for simplified expenses.

Vehicle expenses

Instead of tracking fuel, insurance, repairs, MOT, road tax, and depreciation, claim:

• 45p per mile for the first 10,000 business miles in the tax year
• 25p per mile after 10,000 miles

When to use it: If you drive a lot but your actual vehicle costs are average or low.

When NOT to use it: If you drive a newer car, have high fuel costs, or drive more than 15,000 business miles per year — your actual costs might be higher than the flat rate, so keep receipts and claim the real amount.

Working from home

If you work from home (e.g., doing admin, quotes, invoicing), claim a flat rate:

• 25–50 hours per month: £10/month
• 51–100 hours: £18/month
• 101+ hours: £26/month

You don't need to prove your actual utility bills. Just estimate your hours worked from home.

If you have a dedicated home office and high bills, you can instead claim a proportion of your rent, mortgage interest, council tax, utilities, and internet based on floor space percentage. But this requires receipts and calculations.

CIS Bookkeeping for Subcontractors

If you're a CIS subcontractor (plumber, electrician, builder working for contractors under the Construction Industry Scheme), your bookkeeping needs one extra step: tracking CIS deductions.

How CIS Works

When a contractor pays you:

• They verify you with HMRC and check your CIS status (gross payment or net payment)
• If you're registered for gross payment (0%): they pay you the full amount
• If you're registered for net payment: they deduct 20% tax from your invoice
• If you're not registered: they deduct 30% tax

Each month, the contractor gives you a CIS statement showing:

• Gross amount (what you invoiced)
• Deduction (20% or 30%)
• Net amount (what you were paid)

How to Track CIS in Your Books

Add these columns to your income tracker:

• Gross amount: The full invoice value
• CIS deduction: 20% or 30% withheld by the contractor
• Net received: What actually hit your bank account
• CIS statement ref: Contractor name + month (e.g., "ABC Builders – April 2026")

At the end of the tax year, total up your CIS deductions. When you file your Self Assessment return, enter this total in the CIS section. HMRC will credit it against your final tax bill.

Key point: CIS deductions are not expenses. They're advance payments of your Income Tax and National Insurance. You'll get a refund if you overpaid, or you'll owe more if you underpaid.

Example

Job: Bathroom refit for ABC Builders

• Gross invoice: £2,000
• CIS deduction (20%): £400
• Net received: £1,600

In your bookkeeping:

• Record £2,000 income (this is your taxable income)
• Record £400 CIS deduction (you've already paid this to HMRC via the contractor)
• Reconcile: £1,600 should appear in your bank account

At year-end, if your total CIS deductions were £6,000 and your actual tax bill is £4,500, you'll get a £1,500 refund.

When Do You Need Accounting Software?

You must use MTD-compatible accounting software if:

• Your total qualifying income (from self-employment + property) is over £50,000 (as of April 2026)
• You're VAT registered

MTD (Making Tax Digital for Income Tax) requires you to keep digital records and file quarterly updates to HMRC via software like Xero, QuickBooks, or FreeAgent.

If your turnover is under £50k, you're not required to use software — a spreadsheet or Notion template is fine.

Software vs Spreadsheet: When to Upgrade

Use a spreadsheet if...	Use software if...
Turnover under £50k	Turnover over £50k (MTD required)
Simple income and expenses	Multiple income streams, stock, assets
You have time to enter transactions manually	You want bank feeds and automation
Not VAT registered	VAT registered
Just you (no employees or subcontractors)	You employ staff or pay subcontractors (payroll, CIS returns)

For micro sole traders (under £20k turnover), a well-organized spreadsheet is usually enough.

When Do You Need an Accountant?

You can file your own Self Assessment return if your finances are straightforward. But consider hiring an accountant if:

• Your turnover is over £50k and you're unsure how to use MTD software
• You're thinking about switching from sole trader to limited company
• You have complex expenses (home office, vehicle lease, partnership income)
• You want someone to double-check your numbers and optimize your tax bill
• You've fallen behind on bookkeeping and need rescue services

A good accountant will cost £400–£1,200 per year depending on complexity. For most micro sole traders, this is overkill — but if your time is worth more than the accountant's fee, it's a good investment.

Common Bookkeeping Mistakes to Avoid

1. Mixing personal and business money

Use a separate bank account or clearly label business transactions. If you mix them, you'll spend hours each January trying to separate business from personal.

2. Losing receipts

HMRC can ask to see proof of expenses up to 5 years later. Take photos of receipts immediately and store them in a folder (Google Drive, Dropbox, or a shoebox).

3. Forgetting to record cash income

If you take cash payments, write them down immediately. Cash income is still taxable. HMRC will spot unexplained deposits in your bank account.

4. Claiming non-allowable expenses

You can't claim:

• Clothes (unless it's protective workwear like steel-toed boots or hi-vis jackets)
• Commuting from home to your first job (but travel between jobs is allowable)
• Fines or parking tickets
• Personal phone bills (only the business use portion)

For a full breakdown of allowable vs non-allowable expenses, see our UK sole trader expenses guide.

5. Not tracking CIS deductions properly

If you're a CIS subcontractor and you don't track your CIS deductions, you'll either overpay tax or underpay and face penalties. Reconcile CIS statements monthly.

6. Waiting until January to start bookkeeping

If you wait until the Self Assessment deadline, you'll forget which receipts were for what, lose invoices, and make errors. Do it weekly.

Tools to Simplify Bookkeeping

If you want a middle ground between spreadsheets and expensive accounting software, consider a Notion template.

Our UK Freelancer Business OS includes:

• Income and expense tracker with automatic profit calculation
• CIS deduction tracker for subcontractors
• Mileage log with 45p/25p rate calculator
• Invoice template and client database
• Self Assessment tax year summary (ready to copy into your tax return)

It's designed for UK sole traders who want to stay organized without paying £30/month for software they don't need.

Summary: Your Bookkeeping Checklist

✅ Keep records for at least 5 years after the 31 January deadline

✅ Track income (all invoices, cash, and CIS statements)

✅ Track expenses (materials, tools, vehicle, insurance, phone, etc.)

✅ Log business mileage if claiming 45p/mile simplified expenses

✅ Reconcile CIS statements monthly if you're a subcontractor

✅ Separate business and personal money (or clearly label transactions)

✅ Do bookkeeping weekly (not annually in January)

✅ Use MTD software if turnover is over £50k

✅ Consider an accountant if your situation is complex

Bookkeeping doesn't have to be complicated. Keep accurate records, stay on top of it weekly, and you'll breeze through your Self Assessment return.

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Disclaimer: This article is for information only and does not constitute professional tax or legal advice. Tax rules change regularly. Consult a qualified accountant for advice specific to your circumstances.

Related Articles

• What Expenses Can a Sole Trader Claim? Complete HMRC Guide
• CIS Tax Deductions for UK Contractors: Complete Guide
• Making Tax Digital for Income Tax: What Sole Traders Need to Know
• Sole Trader vs Limited Company: UK Tax Comparison