# How to do your Self Assessment with AI (UK)

You cannot let general AI file your UK Self Assessment - it invents figures and law. Use AI to keep income and expenses organised all year and prep your SA103 numbers, so filing is a review. You submit via HMRC or your accountant.

## Steps
1. Do you even need to file?: If your self-employed income is £1,000 or less you may not need to file at all; above it you can deduct allowable business costs instead. Have the AI watch the £1,000 trading allowance and tell you which side of it you are on, so you find out well before the deadline rather than after it.
2. Keep clean records all year: Self Assessment goes wrong when it is reconstructed from memory at the last minute. Have an AI operating system log every payment in and out as it happens, attach receipts, and categorise each one - sales income, allowable expense, personal, or query - flagging anything it is unsure about, so by 31 January the figures already exist instead of needing to be rebuilt.
3. Prep the SA103 figures for your review: The SA103 supplementary page reports your self-employment turnover and expenses alongside the main SA100 return. Have the AI assemble those totals - income, expenses by category, and profit - into a clear summary you can check line by line, so filing becomes a review rather than a reconstruction.
4. Set the tax money aside before it is due: The tax you owe is due by 31 January, and if your bill is over £1,000 you will usually also make payments on account by 31 January and 31 July. Have the AI estimate what to set aside from each payment you receive, so the bill is money you have already parked, not a surprise.
5. Review and submit - the line AI does not cross: You - or a qualified accountant - check the prepped figures, confirm what is allowable, and submit the return through your HMRC online account. The AI does the legwork; a human owns the return.

## FAQ
Q: Can AI do my Self Assessment?
A: Not the filing, and you should not ask a general chatbot to try. Tools like ChatGPT and Claude have been shown to cite wrong tax rates and invent HMRC rules and case law, so they cannot be trusted to compute or submit a return. What AI can do safely is different - it keeps your income and expenses organised all year and prep your SA103 figures so filing is a review, not a reconstruction. You, or your accountant, still review and submit through HMRC.

Q: When is the Self Assessment deadline?
A: For the 2025 to 2026 tax year, the online return and the tax you owe are both due by 11:59pm on 31 January 2027. A paper return is due earlier, by 31 October 2026. If you are new to Self Assessment you must register with HMRC by 5 October 2026 to get your Unique Taxpayer Reference in time. If you make payments on account, the second one is due by 31 July.

Q: What is the SA103?
A: The SA103 is the self-employment supplementary page of the Self Assessment tax return. You file it alongside the main SA100 to report your self-employment turnover and expenses. There are two versions - SA103S (short) and SA103F (full). Keeping your income and expenses categorised all year is what makes the SA103 quick to complete, because the totals it needs already exist.

Q: Do I still need an accountant?
A: For anything beyond a simple return, yes - and AI does not change that. A qualified accountant should own your tax return and any planning or judgement calls, especially on what is genuinely allowable. Using AI to keep clean records and prep the figures does not replace your accountant; it makes their job faster and cheaper because they receive organised numbers instead of a shoebox of receipts.

Q: Is it safe to use AI for my tax return?
A: It is safe to use AI to organise your records and prepare figures for your review. It is not safe to let a general chatbot compute or file your return, because these tools fabricate tax rules and figures, and a wrong return is your legal responsibility, not the AI's. The safe pattern is a clear split - AI does the bookkeeping and preparation all year; you or your accountant review and submit.

Corey does this for you. Start with Corey, 28 days on us: https://getcorey.ai/get-started