Begin with the processing summary
A merchant statement can look complicated because several kinds of costs are reported together. Start with the summary page. Find total card sales, refunds, chargebacks, deposits and total fees for the month. Confirm that the sales volume is close to your own records and that deposits reconcile with your bank account after refunds and adjustments.
The summary establishes the two numbers needed for a useful comparison: processed volume and total processing cost. Keep equipment purchases, software subscriptions and unrelated service charges separate when possible.
Understand interchange and assessments
Interchange is a set of wholesale fees associated with the card type and transaction conditions. Assessments are network charges. These costs can vary with rewards cards, debit cards, keyed transactions and whether required data was captured. They are not usually controlled by the sales organization in the same way as its own markup.
Your statement may list many interchange categories. You do not need to memorize them. Look for unusual changes in card mix or a rise in transactions that were downgraded because they did not meet preferred data or timing requirements.
Identify processor and service charges
Next, locate the processor markup and recurring charges. Common examples include per-transaction fees, monthly service, PCI-related charges, gateway fees, batch fees, chargeback fees and equipment costs. Names differ by provider, which is why an itemized explanation matters.
Mark any fee you cannot connect to a service you use. Ask for a plain-English definition, whether it is recurring and whether it can change. The answer should be specific enough to put in writing.
Calculate the effective rate
Divide total processing fees by total card volume, then multiply by 100. For example, $1,200 in processing fees on $40,000 in sales equals a 3.0% effective rate. This number is not a complete diagnosis, but it is a practical monthly benchmark. Compare the same categories and the same time period when reviewing alternatives.
Review patterns, not one isolated month
Seasonality, refunds, large tickets and card mix can change the result. Review at least three representative months. A trustworthy proposal should explain the assumptions behind any savings estimate and avoid promising a rate before the business is reviewed. The goal is not just a lower-looking number; it is a statement you can understand and a support contact who will explain changes.