What invoice records should a sole trader keep?
Sending the invoice is only half the job. If you are self-employed, sales invoices are also useful evidence of the income and business transactions behind your tax records.
Last reviewed: 17 August 2026.
Sales invoices are part of the evidence behind your records
GOV.UK says self-employed people need records of all sales and income and must be able to identify business transactions. Its examples of proof include sales invoices, bank statements and bank slips.
You do not normally send all of those records with the tax return, but you need to keep them so you can work out your profit or loss and show HMRC the underlying records if asked.
Source: GOV.UK — self-employed records: what records to keep.
How long do self-employed records need to be kept?
For Self Assessment records, GOV.UK says you must generally keep your records for at least five years after the 31 January submission deadline for the relevant tax year. Different or additional rules can apply in particular circumstances, including very late returns and VAT records, so use the rule that applies to your own situation.
Source: GOV.UK — self-employed records: how long to keep records.
Keep a record even after payment
Marking an invoice as paid is useful management information, but it should not erase the invoice. The issued document and the later payment status answer different questions and both can be useful when reviewing your records.
How Klamic helps
Klamic keeps finalised invoices in your invoice history, preserves the issued details and lets you record whether an invoice is unpaid, overdue or paid. Klamic is not bookkeeping or tax-return software, so you still need an appropriate record-keeping process for the rest of your business.
Create the invoice now — or let Klamic remember the repetitive parts.
The free UK invoice generator works without an account. If invoicing is a regular job, Klamic saves your business details, customers and common services and keeps your invoice history together.