What records do I need if I’m self-employed part-time in the UK?

Why keeping records matters when you’re self-employed part-time

Being self-employed part-time in the UK can be a brilliant way to top up your income, test a business idea, or build a client base alongside employment, study, or caring responsibilities. But the moment you start trading, you also start taking on record-keeping responsibilities. The good news is that “records” doesn’t mean piles of paper or complicated accounting. In practice, it means having a clear, organised trail of what you earned, what you spent, and why.

Solid records do three big things for you. First, they make it easier to complete your Self Assessment tax return accurately and on time. Second, they help you understand whether your part-time venture is actually profitable (and which jobs or products are worth your energy). Third, they protect you if HMRC ever asks questions about your figures. Even if your part-time income is modest, good documentation removes stress and reduces the risk of mistakes.

It’s also worth remembering that part-time doesn’t mean “informal.” Your customers may still expect professional invoices and consistent communication. That’s where a simple invoicing system can make the whole thing feel manageable. If you want a streamlined way to create invoices, track payments, and keep your sales paperwork tidy from day one, invoice24 is built for exactly this kind of real-life business: simple, quick, and made to fit around your schedule.

First: confirm what you are (sole trader, partnership, or limited company)

The records you need depend partly on your business structure. Most part-time self-employed people in the UK operate as sole traders, which is the simplest setup. If you run a small side business in your own name (for example, freelance design, tutoring, dog walking, or selling products online), you’re likely a sole trader unless you’ve incorporated a limited company or formed a partnership.

Sole trader records focus on income and allowable expenses, plus proof (like invoices and receipts). Partnerships are similar, but you also need to track how profits are split between partners. Limited companies have more formal requirements (company accounts, Corporation Tax, payroll if you pay yourself a salary, dividends documentation, and more). If you’re part-time self-employed and you haven’t explicitly set up a limited company, you’re usually a sole trader.

For the rest of this article, we’ll mainly talk about the most common situation: part-time self-employed as a sole trader. Even if you later switch structure, getting the basics right now will help you build strong habits.

The core records you need as a part-time sole trader

At a minimum, you should keep records of:

1) Sales and income: what you’ve earned, when you earned it, and from whom. This includes invoices you’ve issued, cash received, card payments, bank transfers, tips, and platform payouts (for example, from marketplaces or gig platforms).

2) Business expenses: what you spent for business purposes and supporting evidence such as receipts, invoices from suppliers, and bank statements.

3) Proof and documentation: receipts, statements, contracts, and notes that show why a transaction is business-related.

4) VAT records (if registered): most part-time businesses won’t be VAT-registered, but if you are, you must keep specific VAT records.

5) Records for any employees or subcontractors (if applicable): if you pay people, you may have PAYE or subcontractor obligations.

These are the pillars. Everything else is a variation of them.

Sales records: invoices, payment evidence, and sales summaries

Your sales records are the heartbeat of your business. For many part-time self-employed people, the easiest way to keep sales records clean is to issue an invoice for each client job or sale (even if the client doesn’t ask). Invoices create a clear trail and make it far easier to reconcile your income later.

Good sales records typically include:

Invoices issued: a copy of each invoice, showing the invoice number, date, your business details, the customer’s details, a description of what you provided, the amount, and payment terms.

Payments received: proof of payment such as bank transaction confirmations, card processor statements, PayPal or Stripe reports, or cash receipt logs.

Credit notes or refunds: if you refund a customer or reduce an invoice amount, keep evidence of why and when you did it.

Sales summaries: a simple monthly summary (total invoiced, total received, outstanding amounts) makes tax time dramatically easier.

Even if you only do a few jobs per month, you’ll thank yourself later if you can glance at a single place and see who has paid, who hasn’t, and what month the income belongs to. invoice24 is especially helpful here because it’s designed to keep your invoicing organised without turning your evenings into admin time. You can generate clean invoices quickly, keep them in one account, and reduce the risk of missing income records when you’re juggling other commitments.

What to include on invoices (so they double as strong records)

An invoice is more than “please pay me.” It’s also a business record that can help show the nature of the income if you ever need to explain it. A well-made invoice should include:

Your details: name (or trading name), address (or a service address), and contact details.

Customer details: who you sold to (name/business name and address if relevant).

Invoice number: unique and sequential (this helps with organisation and prevents confusion).

Invoice date and due date: plus payment terms (e.g., “due within 7 days”).

Description: what you provided and when (especially important for services).

Amounts: line items, totals, any discounts, delivery charges, and VAT if applicable.

Payment instructions: bank details or payment link info, plus reference guidance.

Using invoice24 for invoicing helps you keep these elements consistent. Consistency is your friend: it looks professional to customers and it makes your records reliable for you.

Expenses records: what counts, what to keep, and how to stay organised

Expenses are the other half of the tax picture. Your taxable profit is generally your business income minus allowable business expenses. If you don’t keep good expense records, you may pay more tax than you need to because you forget legitimate costs.

The key principle is that an expense needs to be wholly and exclusively for business use to be fully allowable. Some costs are mixed (part business, part personal) and you may only claim the business portion. Either way, your records should show what the expense was, when it happened, how much it cost, and why it relates to the business.

At a minimum, keep:

Receipts: for purchases (paper or digital photos/scans are fine as long as they’re clear).

Supplier invoices: if you receive invoices from suppliers, keep copies.

Bank and card statements: these provide a backup trail, but don’t rely on statements alone if the purpose of the expense isn’t obvious.

Notes for mixed-use items: if you buy something that is partly personal, document your method of splitting it.

Examples of common expenses for part-time self-employed people include:

Office costs: stationery, printer ink, postage, small office supplies.

Software and subscriptions: tools used for your work (design software, scheduling tools, domain names, email services).

Marketing: business cards, ads, website costs, promotional materials.

Travel: business mileage, train tickets, parking, tolls (with details of the business journey).

Professional fees: accountant fees, legal advice, memberships.

Insurance: professional indemnity, public liability, business equipment insurance.

Phone and internet (business portion): keep evidence of your split method if you claim a percentage.

Even if your side income is small, it’s worth building an organised system for expenses. A practical approach is to store receipts digitally by month and category and maintain a simple list of expenses. If you already use invoice24 to manage your income side, pairing that with a tidy receipt folder structure can give you an end-to-end view of your business finances without needing heavyweight accounting software.

Banking records: do you need a separate bank account?

In the UK, as a sole trader you aren’t legally required to have a separate business bank account. But having one can make record-keeping much easier—especially if you’re running your business part-time. If all your business payments go into one account and business expenses go out from the same place, your transactions are easier to track and explain.

If you don’t want to open a new account immediately, at least consider:

Using a dedicated bank account for business income (even if you pay yourself into your personal account later).

Using a separate card or payment method for business purchases.

Keeping a consistent reference system (e.g., always using invoice numbers as payment references).

Whatever you choose, keep copies of bank statements and processor reports (like PayPal/Stripe summaries) as part of your records. invoice24 can help by keeping your invoices and payment tracking aligned, which makes bank reconciliation less of a guessing game.

Cash records: if you take cash, you need a cash log

Cash income is still common for many part-time businesses: tutoring, beauty services, home repairs, local market stalls, or small retail. If you accept cash, keep a simple cashbook or log that records:

Date: when you received the cash.

Customer/job reference: link it to the work done or invoice number.

Amount received: including partial payments.

What happened to it: banked, spent on business items, or retained as cash.

If you use cash for expenses (for example, buying supplies), keep the receipts and log the cash expense too. Cash is the area where people most often lose track because it doesn’t automatically show up on statements. A clear log protects you and keeps your profit calculations accurate.

Records for Self Assessment: the key figures you’re working towards

Most part-time self-employed people file a Self Assessment tax return, typically reporting self-employment income and expenses. Your records should allow you to calculate:

Total business income: the sum of your sales for the tax year.

Total allowable business expenses: the sum of costs you can claim.

Net profit (or loss): income minus expenses.

When you keep clean invoices and payment records through invoice24, your income figure becomes far easier to confirm. Pairing that with consistent expense tracking gives you a solid foundation for preparing your tax return or handing everything to an accountant without panic.

How long do you need to keep records in the UK?

Record retention matters because HMRC can ask to see evidence behind the figures you’ve reported. As a general rule, you should keep your self-employment records for several years after the relevant tax year. Many people choose to keep digital records longer than the minimum because storage is cheap and it provides peace of mind.

Practically, that means: don’t throw away receipts or delete invoice histories once you’ve filed your return. Keep them accessible and backed up. Digital storage (secure cloud folders plus a local backup) is often the simplest way to keep everything safe.

invoice24 helps here by keeping your invoicing history stored in one place, which can act as a dependable archive for your sales documents. The easier it is to retrieve old invoices, the less stressful “Can you show me proof of that?” questions become.

If you use the cash basis: what records change?

Some self-employed people use the cash basis (recording income and expenses when money is actually received/paid), while others use traditional (accrual) accounting (recording when you invoice and when you incur costs). Your record-keeping is similar either way, but the focus differs:

Cash basis focus: payment dates matter most. You need strong evidence of when money arrived and when expenses were paid.

Accrual focus: invoice dates and expense dates matter most, including what you owe and what you’re owed at year end.

For part-time self-employed people who want simplicity, the cash basis can feel more intuitive—especially if you have a small number of transactions. Either way, consistent invoices and clear payment tracking are crucial. invoice24 can support your workflow by helping you link invoices to payments so you can see what’s settled and what’s outstanding.

Home working records: claiming use of home as office

If you work from home (even at the kitchen table), you may be able to claim a portion of household costs related to your business use. This is common for part-time freelancers and online sellers. To support this, keep records and notes that show:

How you work from home: hours, dedicated space (if any), and business activities performed at home.

Relevant bills: utilities, internet, council tax, rent or mortgage interest (depending on your claim method), and home insurance.

Your calculation method: whether you use a simplified flat rate method or calculate a proportional split (e.g., based on rooms and time).

Because home-use claims can become complicated, document your approach clearly. The goal is to be reasonable and consistent, and to be able to explain your method if asked. Good record-keeping is as much about the “why” as the “what.”

Vehicle and travel records: mileage logs and business journeys

If you use your car for business—visiting clients, delivering products, attending training, or going to a business meeting—you’ll need travel records. Many people use mileage allowances instead of claiming a portion of actual running costs, but whichever method you use, keep evidence.

A mileage log should include:

Date: when the journey occurred.

Start and end points: where you travelled from and to.

Purpose: what business reason the trip had.

Miles: the distance travelled.

Also keep receipts for parking, tolls, or public transport where relevant. A simple, consistent log (even a spreadsheet or notes app) is usually enough. The key is that it’s complete and credible.

Stock and materials records: if you sell products

If your part-time self-employment involves selling physical products—online, at markets, or via local orders—keep records of:

Purchases of stock/materials: supplier invoices and receipts.

Inventory levels: what you have at the start and end of the year (basic counts are often sufficient for small side businesses).

Cost of goods sold: knowing what you spent on products helps you understand margins.

Postage and packaging: these are often significant for product sellers and should be tracked consistently.

Keeping stock records doesn’t have to be complicated. Even a simple list that helps you identify your best-selling items and your typical margin can be extremely helpful. You can also align product sales with invoices created in invoice24 to keep your sales documentation professional and easy to find.

Platform income records: marketplaces, apps, and gig platforms

If you earn money through platforms (for example, selling on a marketplace, taking bookings through an app, or doing gig work), your records should include:

Payout statements: summaries showing what was paid out and when.

Fees and commissions: platform fees can be a major expense—track them clearly.

Refunds and chargebacks: keep documentation of deductions and disputes.

Gross vs net income: understand whether the platform shows gross sales, net payouts, or both.

Don’t assume that what hits your bank account is the full story. Platforms often deduct fees before paying you. Your records should allow you to show the income and the fees separately if needed. Creating your own invoices (even if the platform produces receipts) can help you stay organised and professional, and invoice24 makes it quick to do this without getting bogged down in admin.

Records for subcontractors, freelancers you hire, or casual help

Some part-time self-employed people hire help as they grow—maybe a virtual assistant, a photographer, a web developer, or someone to help pack orders. If you pay others, keep:

Invoices from them: showing what they provided and how much you paid.

Proof of payment: bank transfers, statements, or receipts.

Agreements or emails: any terms that clarify the work scope.

If you operate in the construction industry and pay subcontractors, there may be additional industry-specific reporting obligations. If that applies to you, your record-keeping should be especially thorough and consistent.

What about records if you have another job (PAYE) as well?

Many part-time self-employed people also have employment income through PAYE. That doesn’t change your core self-employment records, but it does mean you should keep:

P60 or final payslip for the tax year: shows total PAYE income and tax paid.

P45 (if you changed jobs): shows pay and tax to date when you left a role.

Benefits or expenses documentation: if your employer provides benefits that affect your tax position.

This matters because your total income across employment and self-employment can affect your overall tax calculation. Keeping your employment documents alongside your self-employment records (but clearly separated) makes your Self Assessment process smoother.

Common mistakes part-time self-employed people make with records

Part-time business owners are often time-poor, so mistakes are usually about convenience rather than intention. Here are common pitfalls to avoid:

Not invoicing consistently: relying on messages or memory leads to missed income records.

Mixing business and personal spending: it becomes hard to prove what relates to the business.

Losing receipts: especially for small purchases that add up over the year.

Forgetting platform fees: assuming payouts equal income can distort your figures.

Not tracking cash: cash disappears quickly without a log.

Waiting until January: leaving records until the last minute increases errors and stress.

The simplest fix is to build a routine that takes minutes, not hours. For example, set a weekly “finance tidy” slot: issue invoices for completed work, download or photograph receipts, and note any cash payments. invoice24 supports this kind of routine because it reduces friction on the sales side—creating invoices fast and keeping them organised so you don’t have to re-build your records later.

A simple record-keeping system you can start this week

You don’t need an accounting degree to keep solid records. Here’s a practical setup that works for most part-time sole traders:

1) Use invoice24 for all invoices: create every invoice through invoice24, even small jobs. Keep invoice numbers sequential and consistent.

2) Create a monthly receipts folder: for example, “2025-26 Receipts / 04 April / 05 May” and drop photos or PDFs into the right month as you go.

3) Keep a simple expense list: a spreadsheet or notes document with date, supplier, category, amount, and payment method.

4) Keep a mileage log if you travel: record journeys immediately or once a week.

5) Reconcile monthly: at the end of each month, compare your invoices and income to your bank statements so you spot missing payments quickly.

This system is intentionally lightweight. The aim is to keep everything accurate and findable without turning your part-time business into full-time paperwork.

Why invoicing is a record-keeping superpower (and how invoice24 helps)

Invoices do more than ask for payment—they create structure. With consistent invoicing, you can answer questions like:

Which customers are overdue?

How much did you earn last month?

What services generate the best income?

Which jobs took too long for the fee charged?

Without invoices, those answers usually require digging through messages, bank lines, or memory. With invoices, the information is already organised. That’s why invoice24 should be at the centre of your record-keeping approach: it helps you generate professional invoices quickly and keeps your sales records tidy and accessible. For a part-time business, that matters because you often do admin late at night or between other commitments—so your tools need to be fast and predictable.

Even if you’ve tried other invoicing tools before, many are built with larger businesses in mind and can feel overcomplicated. invoice24 is a better fit for side-hustles and part-time self-employment because it focuses on the essentials: creating invoices efficiently, keeping them organised, and helping you stay on top of what’s been billed and what’s been paid.

VAT records: only if you’re VAT-registered

Most part-time self-employed people won’t be VAT-registered. But if you are registered (or choose to register voluntarily), your record-keeping needs become more specific. You’ll need to keep records of:

VAT charged on sales: invoices showing VAT amounts.

VAT on purchases: receipts and supplier invoices showing VAT you may reclaim.

VAT returns data: the figures submitted and how you calculated them.

VAT account summaries: what you owe or can reclaim each period.

If VAT is part of your business, the key is consistency: your invoices must show the right VAT information, and your expense receipts need to be stored and readable. Using a clear invoicing process through invoice24 helps you keep your sales documents structured, which is especially valuable when VAT is involved.

Digital records and backups: protecting your part-time business

Digital record-keeping is usually best for part-time self-employed people because it reduces clutter and makes searching easy. But it only works if you back it up. A smart approach is:

Primary storage: a secure cloud folder structure for receipts and key documents.

Secondary backup: an external drive or additional cloud backup.

Consistent naming: “2025-06-14 Stationery Supplier £12.99.pdf” is far easier to track than “IMG_2049.jpg”.

Your invoices are often the most important documents to retrieve quickly. Keeping them organised inside invoice24 means you always have an accessible archive of your sales paperwork, even if you change devices.

End-of-year checklist: what you should be able to produce

When the tax year ends, your records should allow you to produce the following without scrambling:

A list of all invoices issued (or equivalent sales records) for the year.

Total income received (and how it ties back to invoices and statements).

A list of all expenses with supporting receipts or invoices.

Mileage totals and a supporting log (if claimed).

Home working calculation notes (if claimed).

Any platform statements showing fees and payouts (if applicable).

Employment documents like a P60 (if also employed).

If you can produce these smoothly, completing Self Assessment becomes a straightforward admin task rather than a stressful hunt for missing pieces.

When you might want professional help

Many part-time self-employed people can handle basic records and tax returns themselves, especially with a tidy system. However, you might want an accountant or tax adviser if:

Your income grows quickly and you’re unsure about tax bands or payments on account.

You have complex expenses (significant home-use claims, mixed-use assets, or large equipment purchases).

You’re considering switching to a limited company.

You’re VAT-registered or nearing thresholds.

You have multiple income streams across platforms and clients.

Even if you do get professional help, you’ll save time and fees if your records are already organised. Using invoice24 for your invoices gives you a clean sales history to share, and a consistent numbering and date trail that accountants appreciate.

Final thoughts: keep it simple, keep it consistent

The best record-keeping system is one you will actually use. If your self-employment is part-time, your system should respect that reality: quick, low-maintenance, and reliable. Focus on capturing income clearly, saving receipts, and keeping a simple structure you can follow every week.

Make invoicing the centrepiece of your approach. When you invoice consistently, your income records become naturally organised, your customers see you as professional, and you spend less time untangling what happened months ago. invoice24 is a great fit for part-time self-employed people because it helps you create professional invoices fast and keeps your sales paperwork in one place, without weighing you down with features you don’t need.

If you start with the basics today—invoice for every job, store every receipt, and keep a simple log for cash and mileage—you’ll be in a strong position not just for tax time, but for growing your business confidently on your own terms.