What information do I need for a UK Self Assessment tax return?

A useful Self Assessment file starts with a simple question: what happened during the tax year that could affect the return? Gather records by income or transaction type rather than throwing every financial document you own into one folder and hoping civilisation emerges.

Start with the tax year and filing position

Record:

• which tax year you are dealing with;
• whether a return has already been filed;
• whether you are preparing an original return or correcting something;
• any HMRC correspondence relating to that year.

If more than one tax year is involved, keep the records separated by year.

Employment and pension income

Common records include:

• P60s;
• P45s where relevant;
• P11D or benefits information;
• pension income statements;
• details of other taxable employment-related payments.

Self-employment or freelance work

If you traded or worked for yourself, useful information can include:

• sales or income records;
• business bank records;
• expense records and receipts;
• bookkeeping exports;
• details of assets bought for the business;
• previous accounts where they help explain continuity.

Property income

For rental property, gather records such as:

• rental statements or rent received;
• managing-agent statements;
• invoices and receipts for property expenses;
• finance information where relevant;
• dates of ownership or changes in use if they matter to the issue.

Investments, disposals and crypto

Do not assume investment activity is covered merely because a broker or exchange has a dashboard.

Useful records may include:

• dividend and interest statements;
• broker tax reports;
• purchase and disposal records;
• transaction exports;
• crypto exchange or wallet histories;
• details of material asset sales.

Overseas income or cross-border facts

Flag overseas matters early. Depending on the facts, relevant information may include foreign employment, foreign pensions, rental income, investments, businesses, foreign tax paid and residence history.

The important point at the enquiry stage is not to calculate everything yourself. It is to make the cross-border element visible.

What if records are missing?

Missing records are themselves useful information. Make a short list of:

1. what you have;
2. what you know should exist but cannot currently find;
3. where replacement information might come from;
4. figures that are estimates rather than supported amounts.

That makes it much easier to decide what needs reconstructing.

A concise way to ask for help

A useful opening description might be:

I need help with my Self Assessment for one tax year. I had employment income, a small rental property and some overseas investment income. I have my employment and rental records but I am not sure what I need for the foreign investments.

That gives far more useful context than simply writing “need accountant”. YesTax then asks only two follow-up questions before collecting contact details.