A Self Assessment return can look straightforward once the figures are in front of you. The difficult part is often finding the evidence behind those figures. Knowing what records to keep for Self Assessment means you can claim the expenses you are entitled to, answer HMRC questions confidently and avoid a January search through old emails, carrier bags and bank statements.
For sole traders, landlords, contractors, partners and company directors with additional income, good records are not just an administrative task. They give you a clearer view of profit, cash flow and the tax you may need to set aside. They also make it much easier for your accountant to prepare an accurate return.
What records to keep for Self Assessment
HMRC expects you to keep records that support every figure included on your tax return. You do not generally need to send these documents with the return, but you must be able to produce them if HMRC asks to see them.
The records required depend on your sources of income and the reliefs you claim. In practice, this means retaining evidence of money received, allowable costs, tax already paid and any transactions that affect your tax position.
For most people, bank statements are a useful starting point, but they are rarely enough on their own. A bank payment may show that £300 left your account, but not what it was for, whether it related to your business, or whether VAT was included. The invoice, receipt or clear digital record provides that context.
If you are self-employed
Sole traders and freelancers should keep a reliable record of all business income, including sales invoices, till records, payment processor reports, online marketplace statements and bank receipts. Record the date, customer or source, amount and what the payment relates to.
You should also retain evidence for business expenses. This could include supplier invoices, receipts, travel records, mobile phone bills, software subscriptions, advertising costs, professional fees, insurance and training that is directly relevant to your trade. Keep records of stock bought and sold if this applies to your business.
Where an expense has both business and personal use, only the business proportion can normally be claimed. A home internet bill, mobile contract or vehicle cost may be a valid expense in part, but the calculation needs to be reasonable and supported. Recording the basis for your split at the time is much safer than trying to recreate it later.
If you use a vehicle for business journeys and claim mileage, maintain a mileage log. Note the date, destination, business purpose and miles travelled. If you claim actual running costs instead, retain fuel, repairs, insurance and other vehicle records, together with a sensible calculation of business use.
If you receive rental income
Landlords need records of rental income received for each property, including letting agent statements where relevant. Keep tenancy agreements and records of deposits, as well as invoices for repairs, maintenance, insurance, agent fees, safety certificates and other property costs.
The distinction between a repair and an improvement matters. Replacing a broken boiler with a comparable modern model is commonly treated differently from adding a new extension or significantly upgrading a property. Capital improvements may not reduce your annual rental profit, but the paperwork can be valuable when calculating Capital Gains Tax on a future sale.
Keep mortgage interest statements too. Tax treatment for residential landlords has changed over the years, so do not assume the full mortgage payment is an allowable expense. The interest statement gives your accountant the information needed to apply the correct rules.
If you are employed, a director or have pension income
Employment income is often reported to HMRC through PAYE, but you should still retain your P60, P45 where applicable, payslips and details of taxable benefits. Directors should keep dividend vouchers and records of any salary, benefits, pension contributions or loans involving the company.
For pension income, keep pension statements and P60s from pension providers. If you have made personal pension contributions, retain confirmation of the gross contribution and the provider’s details. Higher and additional-rate taxpayers may be able to claim further relief through Self Assessment, provided the contribution is eligible.
If you have other income or gains
Savings interest certificates, dividend statements, foreign income records and details of cryptoasset transactions may all be relevant. Even where HMRC receives some information directly, your own records remain the best way to check that the return is complete.
If you sold a second property, shares, business assets or other chargeable assets, retain purchase and sale contracts, legal fees, estate agent fees, improvement costs and valuations. Capital Gains Tax calculations can depend on records held for many years, particularly where an asset was purchased long before it was sold.
Keep evidence for tax reliefs and claims
Tax reliefs can reduce your bill, but each claim needs supporting evidence. This includes Gift Aid donation records, pension contribution confirmations, childcare details where relevant, and certificates for qualifying investment schemes.
If you work from home, keep a record of the method used to calculate the claim. You may use simplified expenses if you meet the conditions, or calculate a proportion of household costs. The best option depends on your circumstances. Simplified expenses can save time, while a detailed calculation may produce a more accurate result for some businesses.
How long should Self Assessment records be kept?
For most Self Assessment returns, you should keep records for at least five years after the 31 January submission deadline for the relevant tax year. For example, records supporting your 2024/25 return, due by 31 January 2026, should normally be kept until at least 31 January 2031.
There are exceptions. You may need to retain records longer if HMRC opens an enquiry, if you have claimed losses, if you own assets that could give rise to Capital Gains Tax, or if your circumstances are more complex. Records linked to property purchases, major improvements and share acquisitions are often worth keeping until after the asset has been sold and the related tax position is finalised.
Digital copies are generally acceptable where they are clear, complete and legible. A photo of a faded receipt that cannot be read will not help much. Save files in a consistent format, back them up and make sure you can find them by tax year.
A practical record-keeping routine that saves time
The strongest system is usually the one you will actually maintain. For many small business owners, that means using cloud accounting software connected to the business bank account, then reviewing transactions regularly rather than waiting until year end.
Set aside a short slot each week or month to upload receipts, raise invoices and review uncategorised payments. Keep personal and business spending separate wherever possible. A dedicated business bank account makes the audit trail cleaner, reduces the risk of missed income and gives you a more reliable picture of available cash.
Create folders for each tax year and separate them by income, expenses, property, payroll, pensions and tax payments. If you receive paper receipts, scan them promptly. Thermal receipts fade quickly, and a missing receipt is far harder to deal with two years later.
A useful habit is to reconcile your records against your bank account before submitting the return. Check that sales recorded match money received, investigate unusual transactions and make sure expenses have not been claimed twice. This process often identifies missed costs as well as mistakes.
When professional support makes a difference
Keeping records does not mean you need to become your own bookkeeper and tax adviser. The key is providing complete, organised information so that your return can be prepared accurately and your available reliefs can be considered properly.
If your income comes from several sources, you have started trading, bought a rental property or are unsure whether a cost is allowable, getting advice early can prevent expensive corrections later. Stewart Accounting Services can help put a practical bookkeeping process in place alongside your Self Assessment support, giving you more confidence in the numbers throughout the year.
A calm January usually starts with a disciplined February. Put a simple routine in place now, and your records can become a useful management tool rather than a pile of paperwork to fear at tax return time.