Do this calculation first
Before reading anything line by line, find two numbers: total card volume for the month, and total fees charged. Divide fees by volume, multiply by 100.
That is your effective rate. Everything else on the statement is detail explaining how you arrived at it. If that number surprises you, the rest of this guide tells you where it came from.
For context, US merchants paid an average of $1.57 in fees per $100 of card volume in 2024 across the whole market. That average blends together tiny shops and national retailers with negotiated rates, so it is a reference point rather than a target, but an effective rate well above 3% on established card-present volume deserves scrutiny.
The four sections every statement has
Layouts differ wildly between processors, but the content is always these four things in some order.
Summary
Volume, transaction count, gross deposits, fees, net deposits. This is where your two numbers for the calculation live.
Volume by card type
Visa, Mastercard, Amex, Discover, and often a debit split. This tells you your card mix, which determines what your rate should be.
Fee detail
The long section. Interchange, assessments, processor markup, and everything else. This is where the money actually is.
Adjustments
Chargebacks, refunds, and reversals. Usually small, occasionally where something is very wrong.
Reading the fee detail
Work through it in this order.
Interchange
Should be itemized by category. Every processor pays identical published rates, so this section is not where processors differ, unless it has been padded, which is exactly why you want it itemized. If interchange is bundled into a single line with no breakdown, that is a flag.
Assessments
Network fees. Small, fixed, and non-negotiable. Nothing to see here in a normal statement.
Discount rate / processor markup
The processor's actual margin. Under interchange-plus this is a separate visible line. Under flat-rate it does not appear at all, because it is baked into the blended rate. Under tiered pricing it appears as qualified/mid-qualified/non-qualified buckets, which is the least transparent option available.
Per-item / authorization fees
A few cents per transaction. Irrelevant on a $400 ticket, significant on a $9 one. Whether this matters depends entirely on your average ticket.
Monthly and account fees
Statement fee, monthly minimum, PCI fee, gateway fee, batch fee, annual fee. Individually trivial, collectively capable of moving your effective rate by half a point on lower volume.
A worked example
A retail shop runs $85,000 in card volume in a month and pays $2,870 in total fees.
$2,870 รท $85,000 = 3.38%.
For a card-present retail business with a normal card mix, that is high. Card-present transactions carry among the lowest interchange available, so the true underlying cost on that volume is likely well under 2%. The gap between roughly 2% and 3.38% is markup and fees, on this volume, somewhere near $1,100 a month, or over $13,000 a year.
The number itself is not proof of anything. It is the question worth asking.
Red flags
Interchange not itemized
If you cannot see interchange broken out by category, you cannot verify it has not been padded.
Tiered pricing
Qualified, mid-qualified, non-qualified. The processor decides which bucket each transaction lands in, and you cannot audit the decision.
An effective rate far above your quote
The single most common finding. A quoted 2.6% and an actual 3.3% is an ordinary gap, not an unusual one.
Fees that appeared without notice
Rate increases and new line items often arrive as a footnote on a prior statement. Compare month to month, not just against your contract.
A PCI non-compliance fee
Usually means paperwork was never completed. Often avoidable entirely, and worth a phone call.
High non-qualified volume
On tiered pricing, a large non-qualified bucket usually means keyed or downgraded transactions. Sometimes fixable with terminal configuration alone.
What to do with what you find
Compare three months rather than one, since a single month can be seasonally odd. Then take the effective rate, not the quoted rate, to any processor you are evaluating and ask them to beat that specific number on your actual card mix.
If a processor will not read your statement and show you their working, that tells you what you need to know.
236.6B
US noncash payments in 2024, over three quarters by card
Source: Federal Reserve Payments Study
Common questions
What is my effective rate and how do I calculate it?+
Divide your total fees for the month by your total card volume, then multiply by 100. That single percentage is what card acceptance actually costs you. Everything else on the statement is detail explaining how you got there.
What effective rate is too high?+
US merchants averaged about $1.57 per $100, roughly 1.57%, in 2024, though that blends tiny shops with negotiated national accounts. As a rule, an effective rate well above 3% on established card-present volume is worth scrutinizing rather than accepting.
What are the red flags on a merchant statement?+
Interchange not itemized by category, tiered pricing buckets you cannot audit, an effective rate far above your quote, new fees that appeared without notice, and a PCI non-compliance fee that usually means paperwork was never finished.
Why should I compare several months instead of one?+
A single month can be seasonally odd, and rate increases often arrive quietly as a footnote on a prior statement. Comparing three months against each other, not just against your contract, is how you catch changes that were never announced.
Which section of the statement matters most?+
The fee detail. Read it in order: interchange, assessments, processor markup, per-item fees, then monthly account fees. Interchange is identical everywhere, so the markup and the pile of small monthly fees are where a processor's real cost lives.
Or let us read it for you.
Send two or three months of statements and we'll return a line-by-line breakdown within one business day. No cost, no switch required.
More on merchant services and credit card processing, or read the payments glossary.