Self-Assessment Checklist: What You Need to Prepare for Your Tax Return
If you need to complete a Self-Assessment tax return for the 2025/26 tax year, ensuring you have the correct information ready will save time and help avoid errors. We've put together this handy 7-step checklist to help you gather everything required before submitting your return.
Step 1: Personal Information
These are essential details to identify you with HMRC and log into your online tax account.
- Unique Taxpayer Reference (UTR) number: A 10-digit number issued by HMRC when you register for Self-Assessment. You’ll find it on HMRC letters or in your online account.
- National Insurance (NI) number: Required for tax and benefits purposes. You can find it on your payslip, P60, or HMRC correspondence.
- Government Gateway login details: You need these to access details and view information held by HMRC, including making payments and when they are due.
- Contact details: Ensure HMRC has your correct address, email, and phone number for tax-related communication.
Example documents needed: HMRC registration confirmation letter (showing UTR), National Insurance confirmation letter, proof of address (utility bill, bank statement).
Step 2: Income Information
Gather records of all taxable income sources to ensure accurate reporting.
Employment Income (PAYE taxpayers)
- P60: Shows your total salary and tax paid for the year from your employer.
- P45: If you changed jobs during the tax year, this shows income and tax paid up to your leaving date.
- P11D: Lists any benefits-in-kind received (e.g., company car, medical insurance) that may be taxable.
Example documents needed: P60 from your employer, P45 from previous employer (if applicable), P11D statement from your employer.
Self-Employed & Freelance Income
- Income records: Details of invoices, sales, or any other payments received for your work.
- Business expenses: Costs incurred in running your business (see next section).
Example documents needed: Sales invoices, bank statements showing business income, receipts for expenses, VAT returns (if VAT-registered).
Dividend Income
- Dividend vouchers: Issued by companies or investment platforms, showing dividends paid to you.
- Total dividend income – Ensure all dividends received are declared, even those below the tax-free allowance.
Example documents needed: Dividend vouchers, investment tax reports.
Rental Income (Landlords)
- Rental income records: The total amount received from tenants during the tax year.
- Mortgage interest payments: If applicable, record interest paid (not capital repayments) for relief claims.
- Letting agent statements: If using an agent, their statements summarise income and expenses.
- Repairs & maintenance expenses: Invoices for property repairs, servicing, and maintenance.
- Insurance and service charges: Costs related to landlord insurance or building management fees.
Example documents needed: Letting agent statements, mortgage interest statements, invoices/receipts for repairs.
Savings & Investment Income
- Interest received: Bank and building society interest (excluding ISAs, which are tax-free).
- Investment income: Statements showing interest, dividends, or gains from investments.
- Cryptocurrency transactions: Details of any crypto gains/losses for tax reporting.
Example documents needed: Bank interest statements, investment tax summaries, crypto exchange reports.
Other Income Sources
- Capital gains records: If you sold property, shares, or other taxable assets, you need details of acquisition and sale.
- Foreign income: Any overseas earnings or rental income.
- Trusts, estates, or inheritance received: If applicable, details of distributions and tax paid.
- Pensions received: Statements for state, private, or workplace pensions.
- Child Benefit receipts: If earning over £50,000, the High-Income Child Benefit Charge may apply.
Example documents needed: Property sale completion statements, foreign tax certificates, pension provider statements.
Step 3. Allowable Expenses (For Self-Employed, Landlords, and Business Owners)
Reduce your tax bill by claiming allowable expenses related to your work or property.
- Office costs: Stationery, software, rent, utilities for business use.
- Travel expenses: Fuel, train tickets, flights, and mileage for work trips.
- Marketing costs: Advertising, website hosting, and promotions.
- Professional fees: Accountant fees, legal services, and business subscriptions.
- Home office expenses: A proportion of rent, utilities, and internet if working from home.
- Landlord-specific expenses:Mortgage interest, repairs, letting agent fees, council tax (if paid by you).
Example documents needed: Receipts, bank statements, mileage logs, invoices for professional fees.
Step 4. Tax Reliefs & Deductions
These help reduce your taxable income, lowering your tax bill.
- Pension contributions: Contributions to personal or workplace pensions qualify for tax relief.
- Charitable donations: Gift Aid allows higher-rate taxpayers to claim extra relief.
- Student loan repayments: Ensure correct payments are reported if earnings exceed the threshold.
- Marriage Allowance: If eligible, transfer part of your tax-free allowance to your spouse.
- Investment tax relief: EIS, SEIS, and other schemes may qualify for relief.
Example documents needed: Pension provider statements, Gift Aid donation receipts, student loan statements.
Step 5. Making Tax Digital (MTD) Readiness
For self-employed individuals and landlords earning over £50,000, MTD for Income Tax begins in April 2026. Start preparing now.
- Use cloud accounting software: Platforms like Xero, QuickBooks, or FreeAgent simplify tax tracking.
- Keep real-time digital records: Ensure all income and expenses are logged throughout the year.
- Understand quarterly reporting: Instead of annual tax returns, updates will be submitted every three months.
Example documents needed: Accounting software reports, digital invoices and receipts.
Step 6. Key Deadlines
- Paper tax return deadline: 31 October 2025
- Online tax return deadline: 31 January 2026
- Tax payment deadline: 31 January 2026
- Second payment on account (if applicable): 31 July 2026
Step 7. Submit Your Return & Pay Your Tax
- Double-check all income and expenses
- Submit online via HMRC’s Self-Assessment portal
- Pay any tax due via bank transfer, direct debit, or card payment
- Set up a payment plan with HMRC if needed
Need help with your Self-Assessment? Contact us today to get started!
