Personal and business tax

What is a Self Assessment tax form SA100?

Last updated
March 25, 2025

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What is a Self Assessment tax form SA100?

The SA100 is the main document you need to fill when completing your Self Assessment tax return. There are two ways to complete your Self Assessment tax return: you can make an online submission, or download the form SA100 and make a paper submission.

The SA100 is the main document you need to fill when completing your Self Assessment tax return. There are two ways to complete your Self Assessment tax return: you can make an online submission, or download the form SA100 and make a paper submission.

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Self employed accountantsSelf assessment queries
Speak to a self assessment accountant

Free accounting consultation with a self assessment accountant.