Self-Assessment Tax Return Checklist
Gather every document and figure HMRC will ask for before you file — income, expenses, receipts and reliefs — and keep the key UK deadlines in view. Tick each item off, jot the figure next to it, and file with nothing missing and no last-minute panic.
Key HMRC deadlines
For the 2025/26 tax year
This is a general prompt list for a UK Self-Assessment tax return — it is not tax advice, and not every item will apply to you. Always check the official guidance at GOV.UK or speak to an accountant for your own circumstances. Deadlines shown are the standard HMRC dates and can differ for newly-issued returns.
About the Self-Assessment Tax Return Checklist
Filing a UK Self-Assessment tax return is rarely hard because of the sums — it's hard because of the hunt for paperwork. A P60 here, a dividend voucher there, a shoebox of receipts, an interest figure buried in a banking app. The Self-Assessment Tax Return Checklist turns that scramble into a single, orderly list of everything HMRC might ask for, grouped into eight areas: personal and HMRC details, employment income, self-employment and business, property and rental income, savings/dividends/investments, other income and capital gains, expenses and allowable costs, and reliefs, deductions and final checks.
Tick each item off as you find it and use the small note field to record the actual figure or a reference (which account, which document), so that when you sit down to type the return everything is already in one place. The tool also keeps the four key HMRC dates in front of you — the 5 October registration deadline, 31 October paper deadline, the big 31 January online filing and payment deadline, and the 31 July second payment on account — each with a live countdown for the tax year you select. Everything is stored only in your browser: no account, no sign-up, nothing uploaded. Use Export for a JSON backup, "Download PDF" for a printable pack to hand to your accountant, and pair it with the Checklist Generator for any one-off lists.
How to Use the Self-Assessment Tax Return Checklist
- Select the tax year you're filing for. The UK tax year runs 6 April to 5 April, so the 2024/25 year is filed online by 31 January 2026 — the countdowns update to match.
- Add your name and 10-digit UTR at the top if you'd like them on your printed pack (both are optional and stay on your device).
- Work down each category. Tick an item once you've located the document or figure, and remove anything that doesn't apply to you with the trash icon.
- Use the note field under each item to jot the figure or a reference — for example the exact interest total, or "P60 in email from employer" — so nothing has to be found twice.
- Add anything specific to you in the "Add an item" box, and use "Add category" for whole new areas like a partnership or a trust.
- Keep an eye on the Key Deadlines panel. Registering late or missing 31 January triggers automatic penalties, so aim to be ready well before the countdown runs low.
- When you've gathered everything, click "Download PDF" for a clean pack — deadlines plus every item and the figures you noted — to file the return from or hand to an accountant.
- Click Export to save a JSON backup, and Import to reload it next year as a starting point or on another device.
Tip: gather as you go through the year, not in January. Save receipts and statements to one folder each month and this checklist becomes a five-minute final review instead of a weekend of digging.
Frequently Asked Questions
Is my information private?
Yes. Everything you tick and type — including your name, UTR, and any figures — is stored only in your browser's local storage on this device. Nothing is sent to any server and there's no account. Because tax details are sensitive, treat your device and any PDF or JSON export accordingly, and clear the data when you're finished if you're on a shared computer.
When is the Self-Assessment deadline?
For online returns it's midnight on 31 January following the end of the tax year — so the 2024/25 year must be filed and any tax paid by 31 January 2026. Paper returns are due earlier, by 31 October. If you need to register for Self Assessment for the first time, do it by 5 October. The panel above shows a live countdown to each for your selected year.
Do I even need to file a tax return?
Common reasons include being self-employed and earning over £1,000, renting out property, having untaxed income, earning over £150,000, being a company director, or facing the High Income Child Benefit Charge. GOV.UK has a short checker tool. If HMRC has sent you a notice to file, you must complete one even if you owe nothing.
What is a payment on account?
If your tax bill is over £1,000, HMRC usually asks you to pay next year's tax in two advance instalments: the first by 31 January (alongside your balancing payment) and the second by 31 July. It catches many people out, so the 31 July date is included in the deadlines above.
Where do I find my UTR?
Your 10-digit Unique Taxpayer Reference is on previous tax returns, HMRC letters and statements, and inside your Government Gateway account. If you've genuinely lost it, you can request it from HMRC — but allow time, as it can be posted rather than shown online.
Does the checklist store my actual figures securely for HMRC?
The note fields are just a scratchpad to help you assemble your return — they aren't submitted anywhere and aren't a substitute for HMRC's online service or software. Enter your figures into HMRC's Self Assessment service or approved software when you actually file.
Can I add, rename, or delete categories and items?
Yes. Click a category title to rename it, use the trash icons to remove categories or items, add items in the "Add an item" box, and use "Add category" for new areas. Your changes save automatically and appear on the PDF and export.
Is this tax advice?
No. It's a general organising tool to help you gather what a typical UK Self-Assessment needs. Tax situations vary, rules change, and only some items will apply to you. Always check the current guidance on GOV.UK or consult a qualified accountant for your own circumstances.
Does it work offline?
Once the page has loaded it runs entirely in your browser, so you can gather and tick items with no connection. Your data stays on the device where you saved it unless you Export and Import it elsewhere.