Side-hustlers in the UK must keep clear records of all business income and allowable expenses to complete an accurate Self Assessment tax return and respond to any HMRC enquiries. These records form the basis for calculating taxable profit and demonstrating that claims are genuine.
Keeping the right information does not need to be complicated. A simple system that captures minimum requirements for income, expenses and mileage can prevent mistakes, save time at year end and reduce the risk of penalties for poor record keeping.
Why accurate records matter for side-hustlers
HMRC expects every person with self-employment income to retain evidence of their transactions. Without proper records you cannot correctly calculate profit or defend your figures if queried. Even small side-hustles fall under these obligations once income is earned.
Good records also help you understand whether your activity is profitable. By separating personal and business spending you avoid claiming private costs and you gain a clearer view of cash flow and margins. This information supports better pricing decisions and helps you decide when it is time to register for VAT or incorporate.
Minimum income records to keep
You must record every payment received for goods or services. This includes bank transfers, card payments, cash, PayPal, Stripe and marketplace payouts. Record the date received, the amount, the customer or platform, and a brief description.
- Date of receipt
- Amount in pounds
- Payment method and reference
- Invoice number if issued
- Nature of sale (product, service, commission)
Practical template (use a spreadsheet or notebook):
Date | Description | Amount | Platform | Invoice Ref | Notes
Example row: 12 Mar 2025 | Sale of handmade candles | 48.50 | Etsy | INV-0321 | Includes shipping charged to buyer
Retain digital copies of platform reports, bank statements and any invoices you issue. Keep these for at least six years.
Essential expense records and receipts
Only record expenses that are wholly and exclusively for your business. Common examples include materials, packaging, software subscriptions, advertising fees, postage and professional services. For each expense capture the date, supplier, amount, VAT (if charged) and a clear description of the business purpose.
- Date paid
- Supplier name
- Total amount and VAT if shown
- Payment method
- Business purpose
Practical template:
Date | Supplier | Description | Net Amount | VAT | Total | Receipt Saved
Example: 05 Apr 2025 | Royal Mail | Postage for 12 orders | 18.75 | 0.00 | 18.75 | Yes – photo in folder 2025-04
Keep original receipts, invoices or bank statements. For online purchases save PDF confirmations and take clear photos of paper receipts. Sort files by month to make year-end summarising easier.
Mileage and vehicle expense records
If you use a car, van or motorcycle for business journeys you can claim either a mileage rate or actual running costs. In both cases you must keep a log of business miles. Record the date, purpose of the trip, starting and ending postcodes and total miles driven.
Simple mileage template:
Date | Journey (from–to) | Business Purpose | Miles | Rate | Claim Amount
Example: 18 Feb 2025 | Liversedge to Leeds drop-off | Deliver customer order | 18 | check current rate | calculate accordingly
If claiming actual costs instead, also keep receipts for fuel, insurance, servicing and MOT. You must apportion private and business use reasonably. A mileage diary or smartphone app that timestamps journeys provides strong evidence.
How to organise and store records efficiently
Choose one consistent method. Many side-hustlers use a combination of cloud storage and spreadsheets. Create folders for each tax year (for example “2024-25 Income”, “2024-25 Expenses”, “Mileage”). Scan or photograph every paper document immediately.
At the end of each month, reconcile your records against bank statements. This habit takes less than an hour and prevents errors building up. Free or low-cost tools such as Google Sheets, Excel or basic accounting apps can generate summaries for Self Assessment. Always back up digital files.
Remember that record-keeping rules and thresholds change. Check the latest guidance on GOV.UK before each tax year.
Turning records into accurate tax returns
Once your records are complete, summarise totals for the tax year. Add all income, then deduct allowable expenses to reach taxable profit. Use your mileage log or vehicle cost records to calculate the motor expense figure. Transfer the final numbers to your Self Assessment via the HMRC online service.
Keep a copy of the completed return and all supporting workings. If your turnover grows you may need to consider VAT registration or moving to limited company status; your records will provide the data needed to make that decision. Corporation tax principles differ from self-assessment, so review requirements on GOV.UK or seek professional advice when the time comes.
Making record-keeping a sustainable habit
Treat record-keeping as part of the side-hustle routine rather than a year-end panic. Spend ten minutes after each sale or purchase to log it. Set a calendar reminder to reconcile accounts on the last day of every month. Review cash flow and margins quarterly so you can adjust pricing or control costs early.
Side-hustlers who maintain clean records report fewer stress points at tax time and a clearer understanding of their business performance. The same disciplined approach also prepares you if you later apply for support programmes such as the free desks and mentoring offered at Loomworks in Liversedge.
Frequently asked questions
Do I need to keep records if my side-hustle income is very small?
Yes. HMRC requires records for any self-employment income regardless of the amount. Even if below the trading allowance you should still keep basic evidence in case of enquiries. Accurate records also help you decide when your activity requires a Self Assessment tax return.
Can I use my bank statements as proof of income and expenses?
Bank statements show that money moved but do not explain the business purpose. You must add descriptions, invoices or receipts to demonstrate that each item is allowable. Statements alone are rarely sufficient if HMRC asks for more detail.
What is the easiest way to track mileage for tax purposes?
A simple notebook or mobile app that records date, journey purpose and miles is effective. Capture starting and ending postcodes for each business trip. Review current approved mileage rates on GOV.UK each year before calculating claims.
How long must I keep my side-hustle records?
You should normally retain records for six years from the end of the tax year they relate to. This allows time for HMRC to make enquiries. Digital copies are acceptable provided they are clear and complete.
When should I move from spreadsheets to accounting software?
Move when the volume of transactions makes manual entry time-consuming or error-prone. Software can automatically import bank data and generate reports for Self Assessment. Choose a system that matches your current needs and scales with your business.
Related reading: How is corporation tax handled in startup joint ventures?, How should UK startups price products for international customers?, How does HMRC determine if a worker is employed or self-employed?. Browse all tax & finance guides or apply to Loomworks.