Find three numbers first
Total card volume for the month, total fees charged, and the total number of transactions. Everything else on the statement is supporting detail — these three numbers are what you'll use to judge whether your pricing is reasonable.
Do the division
Total fees divided by total volume gives your effective rate as a percentage. Total fees divided by transaction count gives your average cost per transaction. Those two figures together tell you far more than the 'rate' printed on your original contract.
Scan the fee list for anything you can't explain
Most statements bury a handful of recurring charges among the transaction detail. It's worth reading line by line at least once.
- PCI non-compliance fees you could remove by completing a questionnaire
- Gateway or terminal fees for equipment or services you no longer use
- Monthly minimums you're not hitting
- Annual fees that only appear once and are easy to miss
- Statement, batch or 'regulatory' fees charged per day or per month
Compare three months, not one
One month can be unusual due to seasonality or a one-off charge. Three consecutive months shows the real pattern and catches annual fees that only appear once, which a single-month review would completely miss.
Understand the summary vs the detail pages
Most statements lead with a summary page showing totals, followed by pages of per-transaction detail. The summary is enough for a health check; the detail pages matter if you suspect a specific error or an unusually priced batch of transactions.
Look for downgrades
A 'downgrade' happens when a transaction that should have qualified for a lower interchange category gets bumped into a more expensive one, often due to missing data or a delay in settlement. If you see unfamiliar tier names like 'non-qualified' repeatedly, that's worth investigating.
Cross-check against your POS reports
Your point-of-sale system's own sales reports should roughly match the volume on your statement. A mismatch, even a small one, is worth asking about — it can point to timing differences or, occasionally, an error worth catching early.
When a statement is genuinely hard to read
Some legacy processors format statements deliberately obscurely with tiered pricing and vague labels. If yours takes more than the promised ten minutes and still doesn't make sense, that difficulty is itself useful information about the provider.