The short answer
A lender must verify the income used in its affordability assessment; self-certification is not allowed. If you are self-employed, expect the lender to examine business accounts, tax calculations and bank statements rather than relying on payslips. Requirements vary, but two or three years of evidence is common.
What to gather before applying
- Finalised business accounts, commonly covering the last two or three years.
- Your HMRC SA302 tax calculations and matching tax year overviews.
- Personal and business bank statements, normally covering several recent months.
- Proof of identity, address and deposit, including evidence for any gift.
- Details of loans, credit cards, childcare, maintenance and other regular commitments.
Make sure names, addresses, income figures and accounting periods agree across the application and documents. Explain genuine one-off movements rather than leaving a lender to guess.
Sole trader, partnership or limited company
The figure a lender considers can depend on the business structure and its own policy. A sole trader may be assessed from taxable profit. A partner may be assessed from their share of partnership income. For a limited-company director, some lenders focus on salary and dividends while others may consider a share of retained profit. This is one reason the same application can produce different outcomes with different lenders.
How lenders look at changing income
A rising income does not guarantee that the latest year will be used in full, and a falling year may receive closer scrutiny. Lenders may average periods, use the latest or lower figure, or ask why profits changed. Contracts, management accounts or an accountant's explanation can provide context, but they do not replace the evidence a lender requires.
Worked preparation example
Sam is a sole trader with taxable profits of £42,000 and £48,000 in the latest two years. A simple two-year average is £45,000, but this is not a promise that a lender will use £45,000: its method, Sam's expenditure and the mortgage term still matter. Sam uses the buying-power calculator as an early planning range, not a lending decision.
Timing your application
Speak to a lender or regulated mortgage adviser before changing salary, dividends or accounting dates purely for a mortgage. Filing the latest return early may give a lender newer evidence, but tax and business decisions should still be commercially and professionally sound. Avoid taking new credit or moving deposit money repeatedly without keeping a clear paper trail.
If you have only one year's accounts
Some lenders consider shorter trading histories, often with more specific criteria or evidence such as experience in the same industry. Others require longer. An Agreement in Principle is still conditional and does not confirm that the income, property or documents will pass full underwriting.
Sources and limitations
MoneyHelper lists the documents commonly requested when applying for a mortgage and explains how lenders assess income, outgoings and affordability. The FCA's responsible-lending rules require evidence of declared income and prohibit self-certification. Lender policies change and this guide cannot identify a suitable product. Send corrections to hello@propertiesandhomes.co.uk.
Reviewed by the Properties & Homes editorial team
Published and last reviewed: 14 August 2026.
Change log: first edition.