I had assumed American Express always cost a British shop more than Visa or Mastercard, and I was wrong about half the shops I had in mind. It is repeated so often that it sounds like a rule. I had repeated it for years. Not once had I checked the rate on the readers most small shops actually use, and when I finally put two of those price lists side by side on 16 September 2026, one from Zettle and one from SumUp, both public, both a single page long, both written for exactly the kind of café and corner shop that tends to believe the rule, it split clean in half. On one reader Amex costs exactly what every other card costs. On the other it costs about 71% more per sale, and the gap hides inside a plan most owners picked to save money.
So amex fees for merchants are not a single number. They depend on which of two doors the shop came in through, and most owners could not tell you which door that was.
Door one: a flat-rate reader
Most small shops take Amex without signing anything with American Express at all. They use a reader from a provider that accepts Amex on their behalf, and the provider sets one price for the lot.
Zettle is the cleanest case of the two. Its UK reader page quotes 1.75% on all cards. An Amex payment costs the shop precisely what a Visa debit payment costs. The old rule simply does not apply there. I find it odd how rarely anyone says so.
The plan that makes Amex expensive again
SumUp shows the other face. Pay-as-you-go is 1.69% on card-reader payments. Its Payments Plus plan cuts that to 0.99%, but only for domestic consumer cards: international, corporate and premium cards, American Express included, stay at 1.69%.
Now take a shop, invented for the arithmetic, doing £10,000 a month on cards with £800 of it on Amex. On pay-as-you-go the Amex £800 costs £13.52, the same as any other £800. Switch to Payments Plus and the rest of the takings drop to 0.99%, but the Amex £800 still costs £13.52, not the £7.92 it would cost at the plan rate. That is £5.60 a month and £67.20 a year. I suspect most owners on that plan have never split their Amex takings out at all, and at £800 a month it is small money, but it is also exactly the corner of the bill the owner believed the plan had fixed, and I am slightly annoyed on their behalf that the page puts it in a sub-clause.
The bigger point is structural, not financial. On that plan every Amex sale is priced at 1.69 against 0.99 for domestic debit, roughly 71% more for the same pound of takings. On a flat plan it is nothing more. Same card, same shop, and the answer to "does Amex cost more" flips on one line of small print.
Door two: a direct American Express agreement
Some shops, usually bigger ones or those whose customers carry a lot of Amex, sign with American Express directly. The terms for that are public. I read the March 2024 version, and the fees turn out to be scattered across four sections and a schedule at the back, so a merchant reading only the section called Discount and Other Fees would miss most of them.
American Express calls its fee the Discount. It can be a percentage, a flat fee per transaction, an annual fee, or any mix of the three, and it is given to you in writing rather than published anywhere. Where the terms mention a Discount Rate without more detail, it is applied to the full amount of the charge including taxes. On a £120 sale that includes £20 of VAT, the rate is charged on all £120.
Payment comes on a default plan of three business days from when Amex receives all the charge data. A business day, in these terms, is a day London banks are open, which excludes Saturdays, Sundays and public holidays. So charge data that reaches Amex on a Friday is paid on the Wednesday. Amex can settle net, taking its fees off each payment, or gross, paying the full amount and invoicing monthly in arrears, with the invoice collected by direct debit ten days after its date.
The smaller obligations never appear in a headline rate. You must keep each charge record for eighteen months and hand it over within fourteen days if asked. A file referral fee of £40 applies if an unpaid balance goes to a third party for collection. A data security non-compliance fee of $5 per card account number, capped at $100,000, can apply if card member information is shared without the consent the terms require. And Amex may build a reserve, withholding payments it would otherwise make, in listed circumstances such as ceasing a substantial part of your operations or selling the business's assets.
An aside about that $5 figure, which has nothing to do with the rate. It is written in US dollars inside an agreement for British shops paid in pounds, and while I had the terms open I went looking for the exchange rate that would turn it into sterling and did not find one in Schedule D. Anyway, back to the price.
What the regulation covers, and what it does not
The Payment Systems Regulator notes that the interchange caps, 0.2% on consumer debit and 0.3% on consumer credit, also reach certain fees relating to some American Express card transactions. My reading is that this concerns arrangements where Amex works more like the four-party schemes, through other issuers. I am not confident enough in that reading to say which Amex cards in a particular till are covered, and I would not rely on the cap applying to your own Amex line without asking your provider in writing.
On surcharging, a personal Amex card is a card-based payment instrument like any other, so the ban on charging a fee for paying with a consumer card applies to it as well. The detail sits in our note on card surcharge rules.
What to do with this
Find out which door you came through
Start with the paperwork you already have. Look at the name at the top of your agreement. If it is your card provider, Amex is priced by that provider and the only question is which rate applies to Amex on your plan. If it is American Express, your Discount sits in a letter, and that letter is worth digging out today.
Price the plan with Amex in it
On a discounted plan, work out your Amex and premium card share of turnover before assuming the plan saves you money. A shop where a quarter of sales arrive on premium, corporate and Amex cards gets far less out of a 0.99% plan than the headline promises.
Put 20 April and 20 October in the calendar
Direct merchants only, and the reason for those two dates is in the section below. Five minutes on the terms page twice a year. That is the only warning some changes will ever give you.
Read Amex's survey figures for what they are
The Amex merchant page reports that 64% of its UK card members say they are more likely to visit retail stores regularly when they know they can pay with Amex, and 70% agree Amex is their payment method of choice for all purchases. Those are numbers Amex reports about its own customers. They may well hold for your shop. They are not, on their own, a reason to accept a rate you have not read.
Amex direct, set against the readers
Three business days is worth comparing, because the owners I picture signing with Amex directly rarely set it beside anything. On the published pages I read on 16 September 2026 for our note on clearing times, Square pays standard transfers the next day including weekends, Zettle pays within one to two business days and not at weekends, and SumUp puts money into its own account the next day at 7am.
Put the Amex plan on the same calendar. A Friday's charge data, received that evening, is paid on the following Wednesday. A Saturday's data counts from Monday, so it lands on that same Wednesday. That is not a fee on the statement. It is cash that arrives up to four days later than it would from a reader, on the card that most often carries the larger basket.
None of that makes the direct route wrong. A lower rate can be worth waiting for, and for a restaurant whose customers pay large bills on Amex it may well be. For a restaurant where a big share of the bill arrives on Amex, a lower negotiated Discount may be worth a slower calendar. I would say the calendar belongs in the decision, next to the rate, on the same line.
When the price can change
This is the paragraph I would read twice. Amex may change the agreement, the Discount included, in one of two ways. It can post revised terms online by 20 April or 20 October each year, taking effect two months later, which in practice means 20 June and 20 December. Or it can give at least two months' notice at any other time.
A direct merchant who skips that page in late April or late October can therefore be on new terms by 20 June or 20 December without anything arriving in the post. I have not found a published history of how often the Discount has moved for small merchants since the March 2024 terms, so I cannot tell you how often these two dates actually bite. The dates still deserve a place in the calendar.
What I could not establish
I had also assumed the 2024 direct terms would state a standard rate somewhere, even a starting one. The March 2024 terms state none, and that assumption was wrong too.
I could not find a published standard Discount Rate for a small UK merchant signing directly with American Express, in the 2024 terms or on the 2 Amex merchant pages I read. Section 4.1 says it arrives in writing, and I have not seen such a letter.
I could not establish how many of the UK's small shops take Amex directly rather than through one of the 3 providers above or another like them. My guess is very few among cafés and corner shops. That is only a guess.
The detail I keep thinking about is the VAT at 20%. A rate applied to the full amount including taxes charges the fee on a base 20% larger than the price of the goods, and I still cannot tell you how many direct Amex merchants have ever noticed it.