What Documents Do You Need for Self-Assessment?
For many individuals and business owners, completing a Self Assessment tax return can feel like a major hurdle, especially if it’s your first time. One of the biggest challenges isn’t the form itself, but knowing which documents and records you need to prepare before you start.
Getting your paperwork wrong or missing information can have real financial consequences:
- Fail to include key documents and you could make errors or underpay tax, increasing the risk of HMRC penalties or compliance checks.
- Neglect to record deductible expenses and you may end up paying more tax than you legally need to.
However, taking the time to gather everything in advance makes the process far smoother and ensures you can accurately report your income, claim all eligible reliefs, and submit your return on time.
In this guide, our experts at Accounting Wise have prepared a clear, step-by-step checklist of the essential documents you’ll need for Self Assessment – whether you’re:
- Self-employed,
- A limited company director,
- A landlord earning rental income, or
- Someone with additional income not taxed at source (such as dividends, savings interest, or foreign earnings).
By the end of this article, you’ll know exactly what paperwork to pull together so that filing your Self Assessment becomes efficient, accurate, and stress-free.
Expert Tip: HMRC can request supporting evidence for your Self Assessment for up to six years after submission. Keeping detailed, well-organised records is the best way to protect yourself from disputes or penalties.
Useful resource: HMRC – Self Assessment tax returns
What Documents Do You Need for Self Assessment?
The specific paperwork you’ll need depends on your personal circumstances – whether you’re self-employed, a landlord, a company director, or have additional untaxed income. However, most taxpayers will need to prepare the following core documents before completing their Self Assessment tax return.
1. Personal Information
Before you begin, ensure your personal details and access credentials are in order. These form the foundation of your Self Assessment submission.
- Unique Taxpayer Reference (UTR): A 10-digit number issued by HMRC that uniquely identifies you for tax purposes. You must include this on your return.
- National Insurance number: Used to calculate your Class 2 and Class 4 National Insurance Contributions if you’re self-employed.
- Government Gateway login details: Required to securely access your HMRC account and submit your return online.
Expert Tip: If you haven’t registered for Self Assessment yet, apply for your UTR well before the filing deadline – HMRC can take up to 10 working days to issue it (longer if you’re based overseas).
2. Income Records
You’ll need to provide accurate evidence of all sources of income earned during the tax year (6 April to 5 April). This helps HMRC calculate your total taxable income correctly and ensures full compliance.
- Self-employment: Copies of invoices, sales records, and corresponding bank statements to verify income received.
- Employment (PAYE): P60 (year-end summary) or P45 (if you changed jobs during the year). You may also need a P11D if you received benefits such as a company car or private medical cover.
- Dividends: Dividend vouchers or company statements if you hold shares in your own limited company or other UK companies.
- Savings interest: Statements from banks or building societies showing interest earned during the tax year.
- Rental income: Letting agent statements or detailed rent and expense logs if you manage your property independently.
- Foreign income: Documentation for overseas earnings, pensions, or investments, including any foreign tax paid (for double taxation relief claims).
3. Expense Records
Comprehensive expense records are essential if you’re self-employed or earning rental income. These support your claims for allowable expenses and ensure you only pay tax on genuine profits.
- Receipts and supplier invoices for goods or services purchased for business use.
- Mileage logs or detailed vehicle running cost records if you use a car for business purposes.
- Utility bills and workspace evidence if claiming home office expenses.
- Insurance, trade subscriptions, memberships, and professional fees.
- Repair, maintenance, and equipment purchase records.
Expert Tip: Keep both digital and paper copies of your expense documents. HMRC can request evidence for up to six years after filing your return, so organised record-keeping is vital.
4. Pension and Investment Records
Pensions, savings, and investments can all affect your tax position, so it’s important to have supporting statements ready when completing your return.
- Pension contributions: Annual statements from your provider showing payments made which is essential for claiming tax relief.
- Investment income: Annual summaries or certificates showing dividends, interest, or bond income (including ISAs where relevant).
- Capital gains: Complete records of property, share, or asset disposals, including purchase and sale prices, legal fees, and other associated costs.
5. Other Relevant Documents
Depending on your personal or family circumstances, you may also need the following:
- Child Benefit details: If you or your partner earn over £50,000, you may need to repay part of the benefit under the High Income Child Benefit Charge.
- Student loan statements: HMRC uses this information to calculate repayments due through Self Assessment.
- Gift Aid donations: Keep records of any donations to registered UK charities to claim higher-rate tax relief if eligible.
- Other income sources: Such as tips, freelance work, commission, or casual earnings not taxed at source.
Useful resources:
