Guide
How to check supplier invoices with AI before you pay
ChatGPT or Claude can check a supplier invoice against the purchase order before anyone pays it. Paste the invoice, the purchase order and the delivery or timesheet record, with the bank details you have on file, and ask for the same checks every time: the supplier's name and tax number match; the bank details match the ones on file; every line's quantity times rate is redone, then the subtotal, tax and total; the items, quantities and prices match what was ordered and received; tax and payment terms are right; and nothing was billed twice. The answer is approve or hold, with the reason and the action that clears each hold. Changed bank details always mean hold, confirmed by phone on a number you already have.
Short answer
- Bank details first: changed means hold.
- Every line recalculated.
- Invoice against order and receipt.
- Approve or hold, with the action that clears it.
The brief to copy
Invoice check brief
"Check this invoice before payment.
Supplier: legal name, address and tax number match the order and past invoices; the invoice is addressed to our correct company name.
Bank details: compare with the details on file. If they differ, or anything says the bank details have changed, the result is hold.
Arithmetic: for every line, quantity × rate = line total; then subtotal, discount, tax, total. Show each calculation.
Order and receipt: flag items not on the order, quantities over what was received and rates above what was agreed. Say if there's no receipt record.
Tax and terms: the rate and due date as agreed. Duplicates: the same invoice number, or the same amount within 60 days.
Decide: approve only if everything passes; otherwise hold, with each reason and the one action that clears it. Put the bank result on its own line.
Invoice, order, receipt, bank details on file: [paste]"
A worked example
Illustration: a made-up business. A café group receives an invoice from its coffee supplier for October, and the email with it says the supplier has a new bank. The check returns:
From the check
Bank details: hold. The account number differs from the one on file, and the email says the details changed. Action: call the supplier on the number in the contract, not the one in the email.
Arithmetic: espresso beans 40 kg × 18.00 = 720.00 ✓. Milk 60 crates × 22.50 = 1,350.00, invoiced as 1,530.00 ✗ (180.00 over). Subtotal invoiced 2,250.00; recalculated 2,070.00.
Order and receipt: the order and the delivery note both say 60 crates; the price per crate matches the agreement.
Tax and terms: rate as on past invoices; due in 30 days, as agreed.
Duplicates: none.
Result: hold. 1. Confirm the bank change by phone. 2. Ask for a corrected invoice for the milk line.
The office manager calls the supplier on the contract number. The supplier had not changed banks: the email was not from them. Nobody paid.
What stays with a person
- Approving the payment. The check only says approve or hold.
- Confirming any bank change by a second channel you already trust.
- Checking the recalculated totals before asking the supplier to correct.
- Choosing the account: a business account for finance data; on a personal plan, turn off model training first.
- Saving the brief, so every invoice gets the same checks.
Next step: save the brief
A check you run on every invoice belongs where you can reuse it. ChatGPT prompts for finance, saved shows where to keep it with the other finance prompts. For staff expense claims, see checking expense claims against policy.
Skills for this
- Operations and adminVendor invoice check before paymentChecks a vendor invoice against the PO or quote: details, arithmetic, tax, terms, duplicates, and changed bank details; returns approve or hold.
- FinanceExpense policy checkChecks expenses against your expense policy, line by line: pass, flag, or fail with the rule quoted, missing receipts, and out-of-policy totals.
- FinanceOverdue invoice reminder emailsWrites overdue invoice reminders by stage, from before due to 30+ days late, firm but polite, with the invoice details and how to pay up front.
- FinanceMonth-end close checklistBuilds a month-end close checklist for a small company: reconciliations, accruals, deferred revenue, payroll, and review, with owners and day offsets.
Questions
Can AI check invoices?
It can do the first pass before a person approves: match the supplier, compare the bank details with the ones on file, redo every line's arithmetic, compare the invoice with the purchase order and what was received, check tax, terms and duplicates, and return approve or hold with the reason. A person still approves the payment.
What should an invoice check look for first?
Changed bank details. A new account number, or an email saying the details have changed, is a hold until someone confirms it through a second channel; the FBI's advice on business email compromise is to verify account changes that way, for example by calling a number you already have.
Is it safe to put invoices into ChatGPT?
Use a business account that doesn't train on your data by default, and the tool your company approved for finance data. On a personal plan, model training is on until you turn it off. Remove bank details the check doesn't need, or compare them yourself.
AI skill
Have your AI check a vendor invoice before you pay
Put this skill in AI Skill Pod and everyone on your team gets it in their Claude, Cursor or ChatGPT (Pro, Business, Enterprise): one invite link, free to start. Vendor invoice check before payment has your AI check each supplier invoice: the supplier matched, bank details checked first, every line recalculated, the order and receipt compared, tax, terms and duplicates, then approve or hold with the one action that clears each hold.
14 days free · No card needed
Sources
- FBI IC3: Business Email Compromise, the $55 billion scam (11 September 2024) — "Use secondary channels and/or two-factor authentication to verify requests for changes in account information" (read 2026-11-05)
- Sage: Three-way matching in accounts payable — the purchase order, the goods received and the invoice compared (read 2026-11-04)
- OpenAI Help: Data controls — on Free, Plus and Pro personal accounts, model training is on by default and can be turned off; read through search-result text (read 2026-11-05)