As of 13 August 2026, AI can only partly calculate an employee's UK net pay.

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 the employee's latest payslip and the relevant employment or benefits records, then copy the gross pay, pay frequency, tax code, National Insurance category, pension details, student loan details and other deductions into the prompt.
   2. Remove unnecessary personal identifiers from the payslip and paste the remaining figures into the chatbot prompt.
   3. Ask the chatbot to identify missing inputs and confirm the tax year before it calculates anything.
   4. Paste any missing payroll details, then ask for the calculation table, assumptions and estimated net pay.
   5. Compare the estimate with the latest payslip line by line, including PAYE tax, employee National Insurance, pension and every other deduction.
   6. Check the tax code, National Insurance category, pension treatment and student loan plan against the payslip and current GOV.UK guidance.
   7. Send any unexplained difference and the calculation table to the payroll administrator or an accountant before using the figure to set pay or make a payroll decision.

   Prompt

   Calculate an estimated UK employee net pay for the current tax year using only the information below and current GOV.UK rules. Do not invent missing figures. If a required input is missing, ask for it before calculating. State the tax year and every assumption. Show separate calculations for gross pay, taxable pay, PAYE Income Tax, employee National Insurance, workplace pension, student loan, salary sacrifice, benefits in kind and other deductions where relevant. Identify whether the tax code, National Insurance category, pay frequency, pension basis and student loan plan could change the result. Give the estimated net pay, a clear calculation table and a list of items I must confirm with payroll. Use pounds sterling and distinguish an estimate from an official payroll result.
   
   Gross pay and pay frequency: [insert]
   Tax code and whether it is cumulative or non-cumulative: [insert]
   National Insurance category letter: [insert]
   Tax year, if known: [insert]
   Workplace pension contribution and whether it uses relief at source, net pay or salary sacrifice: [insert]
   Student loan plan or postgraduate loan: [insert]
   Salary sacrifice deductions: [insert]
   Benefits in kind and taxable expenses: [insert]
   Other deductions: [insert]
   Pay date: [insert]
   Relevant payslip or payroll figures: [paste, removing unnecessary personal identifiers]
   
   After calculating, tell me which figures to compare with the employee's payslip and which questions to send to the payroll administrator. This is not professional advice, and do not present the result as a substitute for an employer's payroll calculation.

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