Glossary · UK
What is SA302 Tax Calculation?
An official HMRC document summarising the Income Tax calculated from a Self Assessment tax return, commonly requested by mortgage lenders as proof of income for the self-employed.
Full Definition
The SA302 is a tax calculation document generated from a submitted Self Assessment return, showing a breakdown of total income, allowances, reliefs, and the resulting Income Tax and Class 4 National Insurance liability for the tax year. It is the standard way HMRC confirms, in writing, what a taxpayer's declared income and tax position was for a given year, and it is most commonly requested by mortgage lenders and letting agents as proof of income for self-employed applicants, company directors, and others without conventional payslips. Since HMRC moved most services online, taxpayers filing through commercial software or HMRC's own online portal generate their own SA302-equivalent by printing or downloading the "tax calculation" from their HMRC online account, alongside a "tax year overview" document that confirms the amount of tax HMRC has on record as due for that year -- lenders typically ask for both together, covering the two or three most recent tax years. Where a return was filed via paper or third-party software that does not support online printing, HMRC can post a paper SA302 on request, though this can take up to two weeks. Lenders use the SA302 and tax year overview to verify that self-reported income matches what has actually been declared to and accepted by HMRC, reducing the risk of applicants overstating income on a separate income proof document. Because the figures come directly from a filed return, any errors or omissions in the original Self Assessment submission will carry through to the SA302, so self-employed borrowers are advised to ensure returns are accurate and filed well before applying for a mortgage.