AI told cafés to surcharge. Surcharging has been banned since 1 October.

In short: We asked five AI tools the card cost questions a café owner would ask. We ran the test twice, on 23 and 26 October 2026. 18 of 46 answers were wrong or misleading. Two tools told a café to add a surcharge. Surcharging on eftpos, Mastercard and Visa has been banned since 1 October. Copilot got 1 of 12 answers right. The right answers came from pages that had already done the work. When the AI had to work it out, it guessed.

Did AI really tell cafés to surcharge?

Yes. On 26 October we asked about a café's card costs. Two tools suggested a surcharge.

• Copilot: “Review whether surcharging (within ACCC rules) could offset costs.”
• Perplexity: “Consider a customer surcharge. Australian rules generally allow you to pass on your reasonable cost of acceptance.”

Both are out of date. Since 1 October 2026 a business can't surcharge eftpos, Mastercard or Visa payments. Perplexity said exactly that in another answer the same afternoon.

Which AI tools got the café question wrong?

The café takes $50,000 a month on cards and pays a flat 1.4%. That's $700 a month. The lowest published rate is Westpac's 0.79% plus $24.75 terminal rental. That's $419.75 a month, a saving of $280.25.

Published rates including GST, checked 25 October 2026. Rental from each provider's published pricing.

Three days earlier the results were different. Google got it right. Perplexity got it wrong. Nothing about the café had changed.

Does AI give the same answer twice?

No. Google AI Mode answered two versions of the café question minutes apart. The first said save $105 with a negotiated rate. The second said Westpac and $280.25.

We asked Copilot about the same café three ways. It gave three answers. None was right.

On 23 October the same three questions got $350, $280 and $3,000.

Where does AI get its numbers?

From whatever page it finds.

• A sales page. Copilot's first café answer had one source: a payment company's own fee calculator. That page says most businesses save $5,000 to $20,000 a year by switching to that company. Copilot divided that by 12 and called it the café's saving.
• US prices. Copilot quoted Square at 2.6% plus 15 cents. That's Square's US price. In Australia Square charges 1.6%.
• Made-up prices. Copilot said Stripe Terminal charges 1.2% plus 20 cents. It said the figure was “not in the supplied results”. Stripe charges 1.65% plus 10 cents.
• Odd sources. For the statement question Copilot listed Techmeme, a ransomware tracking site and a news site. It said no web results were provided.

Can AI check if your statement is too high?

Not reliably. A café pays $1,180 in fees on $72,000 of card sales. That's an effective rate of 1.64%. Every tool got the arithmetic right.

1.64% is higher than every published in-person rate Compayr tracks except Stripe's 1.65%. At Westpac's rate the same month would cost about $594 including rental. That's about $586 a month less.

Three of five tools told the café owner the rate was fine. It's costing about $586 a month.

Will AI tell you what the interchange cut saves you?

For a Square merchant the answer is $0. Square kept its 1.6% rate. On 26 October ChatGPT, Perplexity, Google AI Mode and Claude said so. Copilot's headline said $90 to $150 a month. Its own working further down came to $53.

Can AI handle small sales?

A coffee cart takes 3,000 payments a month at $6 each. That's $18,000. Square charges 1.6%, which is $288. Stripe Terminal charges 1.65% plus 10 cents a payment, which is $597. Square costs $309 a month less.

On 26 October four tools got this right. Copilot's headline said $90 to $120. Its own table said $528. Both are wrong. On 23 October ChatGPT's first line said $75 to $80 and corrected itself further down.

Why does AI get card costs wrong?

• It doesn't hold the rates. It repeats whatever page it finds. If it finds nothing, it guesses.
• Rates moved on 1 October. Many pages were written before then.
• It can't tell a sales page from a price list. A provider's savings claim reads the same as a published rate.
• It sounds sure either way. The wrong answers read as confidently as the right ones.

Other testing found the same. The UK consumer group Which? found AI tools were right on 55% to 71% of money questions. ASIC's Moneysmart warns that general AI tools can give inaccurate or inappropriate suggestions.

How do I work out my real card costs?

1. Find your effective rate. Divide card fees by card turnover for the month. Our statement guide shows where to find both.
2. Compare it at compayr.com.au/compare. It shows each provider's published rate at your turnover, with the date it was checked.
3. Ask the provider for a written quote before you switch.
4. Don't add a surcharge to eftpos, Mastercard or Visa payments. It's banned.

About this test. Five AI tools: Copilot, ChatGPT, Perplexity, Google AI Mode and Claude. Six questions on a café's card costs, a card statement, a Square merchant and a coffee cart. 18 answers on 23 October 2026 and 28 on 26 October. Copilot, ChatGPT, Perplexity and Google AI Mode were used logged out, one run per question. Claude was used in incognito chats with web search on. On 26 October Claude was asked all six questions in one chat. The statement question did not name Australia. AI answers change from day to day, so treat these as examples, not a ranking of the tools. ChatGPT and Claude cited Compayr in some of their right answers. Compayr covers 15 providers with published rates, from the 17 Compayr compares. Compayr is a free merchant payment comparison site. It may receive a referral fee from a provider when a merchant switches through it. This does not affect rankings. This article is general information, not financial advice.