Self Assessment checklist for 2025–26.

This Self Assessment checklist covers the documents to ask clients for on their 2025–26 tax return, the tax year from 6 April 2025 to 5 April 2026. It's grouped by type of income, so you can send each client only the sections that apply to them.

Every item comes with a one-line "why we ask" you can paste into your request. Clients find the right paper faster when they know what it's for, and they're more likely to tell you when something doesn't apply.

Before you use these lists

These are typical examples to tailor to each client, not a list of what HMRC requires you to collect. Start from last year's return, then:

• Keep only the sections that apply. An employee with some savings needs two sections, not eight.
• Name the tax year. "Interest for 6 April 2025 to 5 April 2026" leaves less room for a calendar-year statement than "interest for the year".
• Ask what changed. A new job, a property sold, a first pension payment. Changes are where documents go missing.
• Make "doesn't apply" an easy answer. A blank looks like a document that's still coming.

Key dates for 2025–26

Payments on account are due unless last year's bill was under £1,000, or more than 80% of the client's tax was already paid at source. Checked on 20 October 2026 against Self Assessment tax returns: deadlines and the other GOV.UK pages listed under Sources.

Employment

For anyone who was an employee or a director paid through payroll during the year.

Self-employment

For sole traders and partners. GOV.UK says a sole trader who earned more than £1,000 before costs must send a return. The year-end accounts checklist has the full list for a sole trader's records.

Property

For landlords, including anyone renting out a room or a property they own with someone else.

Savings and investments

For anyone with interest, dividends or investments outside an ISA.

ISA statements aren't needed. Income and gains inside an ISA don't go on the return, so saying so up front saves your client a search.

Pensions

For anyone receiving a pension. Pension contributions are under reliefs and allowances below.

Capital gains

For anyone who sold or gave away shares, property other than their home, crypto assets or other valuable things. The tax-free allowance is £3,000 for 2025–26.

Foreign income

For anyone who is UK resident with income from outside the UK. The Channel Islands and the Isle of Man count as foreign.

Reliefs and allowances

These reduce the tax bill, so they're the items clients forget most.

Copy the full Self Assessment checklist

SELF ASSESSMENT 2025–26: DOCUMENT CHECKLIST
Tax year: 6 April 2025 to 5 April 2026

EMPLOYMENT
- P60 from each job held on 5 April 2026
  Why we ask: it shows the pay and tax for the year.
- P45 from any job that ended during the year
  Why we ask: pay and tax from that job count too.
- P11D, or details of benefits such as a company car or health
  insurance (if any)
  Why we ask: benefits are taxed like pay.
- Work costs your employer didn't pay back
  Why we ask: you may be able to claim tax relief on them.
- Tips or commission not paid through payroll (if any)
  Why we ask: untaxed income must go on the return.
- Your student or postgraduate loan plan (if you're repaying one)
  Why we ask: repayments can be due on the return.

SELF-EMPLOYMENT
- Sales invoices or your record of income for the year
  Why we ask: to work out what the business earned.
- Statements from apps or online marketplaces you sell through
  Why we ask: income received through them counts too.
- Receipts or a summary of business costs
  Why we ask: to claim every cost you can.
- Statements for every account you use for the business
  Why we ask: to find business payments in and out.
- Mileage log (if you use your own vehicle)
  Why we ask: we can claim business travel but not personal trips.
- Invoices for equipment or vehicles bought or sold
  Why we ask: for tax allowances on what you bought.
- Hours worked from home (if you work from home)
  Why we ask: you may be able to claim part of your household costs.
- Copies of your quarterly updates (if you use Making Tax Digital)
  Why we ask: to check the year's figures against what HMRC has.
- Your share of the partnership's profit (if you're a partner)
  Why we ask: it goes on your own return.

PROPERTY
- Rent received for each property, with tenancy dates
  Why we ask: to report the rental income for the year.
- Letting agent statements (if you use an agent)
  Why we ask: they show rent collected and the fees taken.
- Mortgage interest statement for each let property
  Why we ask: finance costs are given relief differently.
- Receipts for repairs and maintenance
  Why we ask: repairs can be claimed against the rent.
- Insurance, ground rent, service charges and bills you paid
  Why we ask: these costs can be claimed against the rent.
- Your share of each property you own jointly
  Why we ask: you pay tax on your share only.
- Purchase or sale paperwork for any property bought or sold
  Why we ask: a sale may also mean Capital Gains Tax.

SAVINGS AND INVESTMENTS
- Interest statements from each bank and building society
  Why we ask: interest over your allowance is taxable.
- Dividend vouchers, or a tax certificate from your platform
  Why we ask: dividends go on the return.
- Annual tax report from each investment platform
  Why we ask: it lists interest, dividends and sales in one place.
- EIS, SEIS or VCT certificates (if any)
  Why we ask: relief on them is claimed through the return.

PENSIONS
- P60 from each workplace or private pension paying you
  Why we ask: pension income is taxable.
- Your State Pension letter showing the yearly amount
  Why we ask: it's taxable but paid without tax taken off.
- Statements for any lump sum or drawdown taken this year
  Why we ask: some or all of it may be taxable.
- Statements for any pension from abroad
  Why we ask: it's reported as foreign income.

CAPITAL GAINS
- What you sold or gave away, with the date and amount received
  Why we ask: to work out the gain.
- What you paid for it, and when
  Why we ask: the gain is the difference.
- Costs of buying, selling or improving it
  Why we ask: they reduce the gain.
- Realised gains report from your investment platform
  Why we ask: it lists every sale for the year.
- A record of crypto asset transactions (if any)
  Why we ask: swaps and sales can count as disposals.
- Any reference from reporting a UK property sale to HMRC already
  Why we ask: so it isn't reported twice.

FOREIGN INCOME
- Statements for foreign interest, dividends, rent, wages or pensions
  Why we ask: UK residents normally pay UK tax on foreign income.
- Proof of tax paid abroad on that income
  Why we ask: you may get relief so it isn't taxed twice.
- Days spent in the UK and abroad (if you moved or travel a lot)
  Why we ask: residence decides what's taxed in the UK.

RELIEFS AND ALLOWANCES
- Gift Aid donations: each charity, date and amount
  Why we ask: higher-rate taxpayers can claim extra relief.
- Personal pension contributions you paid yourself
  Why we ask: higher-rate taxpayers can claim extra relief.
- Child Benefit received, and who received it
  Why we ask: over £60,000 of income, some may have to be paid back.
- Your HMRC statement, or payments on account you've made
  Why we ask: to credit what you've already paid.
- Letters from HMRC received during the year
  Why we ask: so we don't miss anything HMRC has asked or changed.
- Last year's return (new clients only)
  Why we ask: our starting point for this year.
- Your UTR and National Insurance number (new clients only)
  Why we ask: we need both to file your return.

Client-friendly version

The lists above use the words accountants use. Many clients don't know what a P11D is, or whether their bank interest counts. This version asks in plain words, as questions, so a client can work through it without calling you.

Paste it into your request message, and remove the questions that clearly don't apply.

Your 2025–26 tax return: what we need from you

This covers 6 April 2025 to 5 April 2026. Go through the questions
below. Where the answer is yes, please send what's listed. Where it's
no, just tell us. That helps as much as a document.

Did you have a job, or more than one?
  Send the P60 your employer gave you after 5 April 2026. If you left
  a job during the year, send the P45 too. If you had a company car or
  health insurance through work, send the P11D or a note of what it was.

Did you work for yourself, or sell things through an app or website?
  Send your record of what you earned and spent, and the statements
  for any account you used for the work.

Did you rent out a property or a room?
  Send what rent you received, your letting agent's statements, the
  mortgage interest statement and receipts for any repairs.

Did you earn interest, or get dividends from shares?
  Send the yearly statement from each bank, building society or
  investment account. You don't need to send ISA statements.

Do you get a pension?
  Send the P60 from each pension, and your State Pension letter.

Did you sell or give away shares, crypto or a property that isn't
your home?
  Send what you sold, when, what you got for it and what you paid.

Did you have any money from abroad?
  Send the statements, and anything showing tax paid there.

Did you give to charity, or pay into a pension yourself?
  Send a list of Gift Aid donations and your pension statements.
  These can lower your tax.

Did you or your partner get Child Benefit?
  Tell us who received it and how much.

Did HMRC write to you this year?
  Send us the letters.

Please send everything by [due date]. If you're not sure whether
something counts, send it anyway, or ask us.

Sending it

However you send the list, three things decide how fast it comes back.

1. One request per client. Only the sections that apply, all at once, with one place to put everything.
2. A due date ahead of yours. The end of November leaves December to chase and prepare.
3. Reminders that name what's missing. Most clients send the easy items first, then stall on one or two, often the mortgage interest statement or a platform's tax report. A reminder that names them works better than "just checking in".

For timings, see how often to send reminder emails to clients. For the wording of the first email, see the document request email templates.

How to do this in GarnerDocs

Save one template per kind of client, then start each client's request from the one that fits.

• Employee with side income. Employment, savings and investments, and reliefs, plus a "side income" category with income records and costs.
• Landlord. Property first, then savings, capital gains for sales, and reliefs.
• Sole trader. Self-employment first, then reliefs, payments on account and HMRC letters.
• Sections become categories. Your client sees the documents grouped the same way, with "why we ask" under each name as its description.
• Some items are short answers. A Unique Taxpayer Reference or "who received Child Benefit" can be typed instead of uploaded.
• Tailor, then send. Remove what doesn't apply and set your due date. Reminders list only what's still missing.

See Create a template.

Sources

• Self Assessment tax returns: deadlines, GOV.UK (HMRC). Checked on 20 October 2026.
• Self Assessment tax returns: who must send a tax return, GOV.UK. Checked on 20 October 2026.
• Understand your Self Assessment tax bill: payments on account, GOV.UK. Checked on 20 October 2026.
• Pay your Self Assessment tax bill through your tax code, GOV.UK. Checked on 20 October 2026.
• Report and pay your Capital Gains Tax and Capital Gains Tax allowances, GOV.UK. Checked on 20 October 2026.
• Tax on foreign income, GOV.UK. Checked on 20 October 2026.
• Gift Aid and tax relief on pension contributions, GOV.UK. Checked on 20 October 2026.
• High Income Child Benefit Charge, GOV.UK. Checked on 20 October 2026.

This guide is general information, not legal or tax advice. Check the rules that apply to each client.