Glossary · UK

What is SA300 (Tax Calculation Summary)?

The HMRC document showing your Self Assessment tax calculation — how much you owe and why.

Full Definition

The SA300 is the tax calculation summary produced by HMRC (or your tax software) as part of the Self Assessment process. It sets out your total income from all sources, the deductions and reliefs applied, the resulting Income Tax and NI liability, any payments on account already made, and the final balance due (or repayment owed). If you file online, the SA300 equivalent is shown on screen and downloadable as a PDF; for paper filers it is a separate form. Banks, mortgage lenders and letting agents often request an SA302 (the official HMRC version of the same document) as evidence of income rather than the SA300. HMRC can issue the SA302 directly, or it can be downloaded from your HMRC personal tax account for the previous four tax years.