As of 13 August 2026, AI can only partly calculate the UK tax you may owe on your savings interest.

What to actually do

1. Hand it to a person

   The route this page recommends

   A person who owns the outcome does this end to end, worth it when the failure is dear.

2. Use a tool built for this

   Second choice

3. Do it yourself

   The distant third

   A chat interface, chat-fluent skill, and roughly 30 minutes until you can act on the result.

   How to actually do it

   1. Open your bank and building society statements for the relevant tax year and record each account's interest, separating cash ISAs and other tax-free accounts from taxable savings accounts.
   2. Open your payslips, pension records and other income records and total your taxable income, dividends and any tax already deducted from savings interest.
   3. Open the relevant GOV.UK pages on tax on savings interest and personal allowances, then note the links and the rules that appear to apply to your tax year.
   4. Paste the prompt into a chatbot and replace every bracketed slot with your figures, tax year and links, leaving a slot blank rather than guessing.
   5. Paste the model's calculation into a spreadsheet and reproduce each step using your bank totals and the current GOV.UK rules.
   6. Compare the result and assumptions with your statements, PAYE records and HMRC information, then correct any account classification or missing income.
   7. If the result involves unusual income, uncertainty about your tax band or a significant amount of tax, send the records and calculation to an accountant or tax adviser before acting.

   Prompt

   Calculate an estimate of the UK income tax that may be due on my savings interest for the tax year [tax year]. Use only the figures and current GOV.UK rules I provide or link to, and do not invent missing figures. First list the assumptions and identify any information I still need. Separate interest from cash ISAs or other tax-free accounts from taxable savings interest. Use these details: taxable savings interest £[amount]; interest from tax-free accounts £[amount]; other taxable income £[amount]; employment or pension income £[amount]; dividends or other income £[amount]; tax code if known [tax code]; taxpayer details such as basic-rate, higher-rate or additional-rate status if known [details]; and any tax already deducted from savings interest £[amount]. Show each calculation step, explain which allowance or rate you have applied, distinguish an estimate from a confirmed HMRC calculation, and give a low, central and high scenario only where a missing figure makes that necessary. Do not advise me to claim a relief or allowance unless you explain what fact would make it applicable. Link each rule to the relevant GOV.UK page, flag rules you cannot verify as current, and finish with a checklist of figures I must confirm before relying on the result. This is not professional advice.

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