As of 13 August 2026, AI can find out when your tax return is due.

Most people should hand this to a purpose-built tool.

Can you do it?

2 minutesto a draft.

5 minutesto something you’d act on.

Cost, all in£0

Skill neededchat-fluent

Who has to check ityou

What the alternative costsNo priced alternative is provided in the supplied tool data.

If this goes wrong, you may rely on the wrong deadline and face HMRC penalties or interest after filing or paying late.

What to actually do

Use a tool built for this
The route this page recommends
One pick for this task
Julius AI
Julius can analyse a spreadsheet of tax dates or notices, but it does not provide an HMRC deadline lookup, so GOV.UK remains the authoritative check.

Do it yourself

Second choice

A chat interface, chat-fluent skill, and roughly 5 minutes until you can act on the result.

How to actually do it

Open the relevant current tax-return deadline page on GOV.UK and keep it open for comparison.
Gather the tax year or accounting period, the type of return, the filing method, any HMRC notice, and whether you need to file online or on paper.
Paste those details into the prompt, removing your name, address, National Insurance number, Unique Taxpayer Reference and other personal information.
Ask the chatbot to separate the filing deadline from the payment deadline and to provide the GOV.UK source link for each answer.
Compare every date and condition in the response with the GOV.UK page, then save the confirmed dates in your calendar and contact HMRC or a tax adviser if the notice and GOV.UK information do not match.

Prompt

I need to know when my UK tax return is due. Use current GOV.UK information only and give me links to the pages you relied on. Ask me for any missing details before answering. My details are:

- Tax return type: [Self Assessment, company tax return, or other]
- Tax year or accounting period: [insert it]
- Filing method: [online, paper, or unknown]
- Why I need to file: [for example, self-employed, rental income, untaxed income, or HMRC notice]
- Have I registered for the relevant tax service: [yes, no, or unknown]
- Have I received a letter or notice from HMRC: [paste the relevant wording, removing personal information]

Tell me separately:
1. The filing deadline.
2. The payment deadline, if there is one.
3. Whether the deadline depends on facts I have not supplied.
4. The exact GOV.UK page I should check myself.

Do not guess, use outdated dates, or give tax-planning advice. If the details are unclear, say exactly what I need to confirm with HMRC or a tax adviser. This is not professional advice.

Open it prefilled in ChatGPT or Claude, or copy it into Gemini, which takes no prefill link.

Hand it to a person
The distant third
A person who owns the outcome does this end to end, worth it when the failure is dear.

What it gets wrong

AI cannot know which deadline applies if you omit the tax year, filing method, return type or HMRC notice.
AI cannot guarantee that a remembered deadline is current without checking GOV.UK.
AI cannot resolve a conflict between your HMRC notice and the public guidance; HMRC or a tax adviser must confirm it.
AI does not take responsibility if you file or pay late.

Even on a YES, the friction has a name: real time truth, stakes of error and context depth.

How we scored this

Five axes, each scored nought to two by hand: ten means AI carries the task cleanly, and the thresholds that turn a total into YES, PARTLY or NO are published in the methodology. Each axis name links to its definition.

Axis	Score (0–2)
Output	2
Inputs	2
Verification	2
Liability	1
Effort delta	2
Total	9 / 10

The methodology and its thresholds are published in full.

FAQ

Can AI tell me when my tax return is due?: Yes, for a straightforward case, if you give it the tax year and return details and check the result against GOV.UK. It should show the filing and payment deadlines separately because they may not be the same.
What is the deadline for my UK Self Assessment tax return?: It depends on the tax year, whether you file online or on paper, and your circumstances. Use current GOV.UK guidance or give those details to an AI tool that provides the source link, then compare the answer with GOV.UK before relying on it.
Can ChatGPT check my HMRC deadline?: It can help interpret the deadline if you paste the relevant HMRC wording with personal information removed. It cannot replace checking the current GOV.UK guidance or asking HMRC when the notice and public guidance differ.
What happens if I miss my tax return deadline?: HMRC may charge penalties or interest, depending on what was late and the reason. This is not professional advice, and a serious case needs confirmation from HMRC or a qualified tax adviser.

Nearby answers

All Tax returns & HMRC rulings

Assessed by gpt-5.6-luna (gpt-5.6-luna) on 2026-08-13, second-checked by an independent model. Wrong somewhere? Email [email protected] and it gets re-checked.

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