Every card transaction fee is made up of three separate charges stacked together. Most providers just show you the total — here's what's inside it.
When a provider quotes you "1.75%", that single number is actually three fees bundled into one, paid to three different parties. Understanding the split is the fastest way to spot which part of a deal is genuinely negotiable — and which part isn't.
This is paid to the bank that issued the customer's card, as compensation for the risk and infrastructure of extending credit or holding the account. In the UK, interchange fees are capped by regulation at 0.2% for debit cards and 0.3% for credit cards on consumer transactions. This part of the fee is set by Visa and Mastercard's rules — no provider can discount it, because they're not the ones charging it.
A smaller fee paid to the card network itself, for running the rails the transaction travels over. It's typically a fraction of a percent, and again isn't something your provider sets or discounts.
This is the part that's actually negotiable. It's your acquirer's or payment facilitator's margin for underwriting your account, running the app or terminal, handling settlement, support and fraud tools. When two providers quote different headline rates on card payments carrying the same interchange and scheme fees, it's almost always this markup that differs.
Most small business providers (SumUp, Square, PayPal POS) quote a single flat percentage that already bundles all three fees together — simple to budget for, but it means you're paying the same markup on a cheap debit card as an expensive commercial or overseas one.
Larger or higher-volume providers (Worldpay, Adyen, Elavon) can offer "interchange++" pricing: interchange and scheme fees are passed through at cost, and the markup is quoted separately and transparently. It's usually cheaper overall, but only once your volume is high enough that a provider will offer it — commonly cited around £75,000+ a month, though it varies.
American Express typically operates its own network with different, usually higher, acceptance costs than Visa or Mastercard — which is why some providers charge more for Amex, or exclude it altogether. Similarly, cards issued outside the UK or EEA fall outside the domestic interchange cap, which is why "international card" surcharges of 1–2 percentage points are common on online gateways in particular.
Some providers add a small fixed fee per transaction (Stripe's 20p, GoCardless's 20p, Tyl's 5p) on top of the percentage. Fixed fees matter more on small transactions and less on large ones — a 20p fee is 4% of a £5 sale but 0.2% of a £100 one, so weigh it against your actual average transaction value rather than the headline rate alone.