Re-run your card mix before a payment rate change forces a decision

A rate change shows up as a new percentage, not a decision. Pull the charges you actually processed and split the mix before you re-shop. The decision is usually renegotiate, add another acquirer, or surcharge, and the numbers should decide it.

Founders who run day-to-day on a processor often see a headline rate change and assume the answer is to move providers. That skips the part that actually moves the bill: the mix of standard cards, premium cards, and international cards. A blended rate hides the spread. The spread drives the decision.

A rate change is a trigger, not a verdict

Stripe's standard UK card rate is 1.5% + 20p. That baseline is useful, but it is not the whole story. A foreign card settled in your currency can add extra fees. Recent charges with foreign customers can look calm on average while the expensive cases are hidden.

IC+ is the benchmark you should ask for. On 10 October 2026, Stripe's UK list price showed IC+ available only through custom pricing for high-volume businesses or businesses with unusual models. Outside that bucket, your leverage may be another acquirer, not a better quote.

Build the worksheet from actual charges

Use recent real charges, not a forecast. The worksheet should answer the key questions: what you charge, what the mix is, what it costs annualized, and where the offset comes from.

• Pull a recent period of charges. You need enough volume to see the pattern, not just the average.
• Split the mix. Sort standard consumer cards, premium cards, and international cards into separate buckets. Premium card fees are the line item that moves the bill. EEA credit carried a 29p margin, while premium and commercial cards produced an even smaller margin because their interchange is not subject to the caps.
• Annualize the premium cost. Scale the recent processing cost to an annual figure, then compare it to the new rate. Revolut Business charged 1% + £0.20 for online UK-card payments and 2.8% + £0.20 for online payments from all other cards.
• Add the international offset. When the same UK merchant was paid online, a French-issued debit card incurred 1.15% interchange, while a UK consumer debit card incurred 0.2%. Stripe's international card rate was 3.25% + 20p, and a 2% currency conversion fee made a US dollar card settled in GBP cost 5.25% + 20p. Keep the international share as a separate line so you can see how much it adds to the annualized cost.
• Benchmark the acquirer. Compare the blended cost against an IC+ quote, another acquirer, or a surcharge. Put the options and the non-price factors in the same view: settlement timing, dispute handling, and checkout compatibility.

The usual mistake is to treat the cheapest headline rate as the answer. A lower rate can cost more than the spread you saved when it slows settlement, adds chargeback friction, or breaks checkout. Treat the acquirer benchmark as a check, not a default: extra integration work on a new option should be priced against the fee spread.

Use the decision tree before you call anyone

High annualized cost with a small international share points to renegotiation: ask for volume-based pricing, a custom quote, or a clearer IC+ structure. A large premium and commercial share points to another acquirer for that traffic, without moving your whole stack. A large international share with conversion fees as the main cost points to surcharging the affected cards or settling in the customer's currency where your model allows it.

Do not re-shop until the worksheet says the current processor is the problem. Keep the worksheet open while you talk to the processor, and use the mix to choose the next move.