Credit Card Processing Fees Explained
The Three Components of Every Processing Fee
Every time a customer pays with a credit or debit card, three separate entities take a cut of the transaction. Understanding who gets paid, how much, and why is essential for controlling your processing costs. Most small business owners look at their processing rate as a single number, but that number is actually three fees stacked on top of each other.
Interchange Fees (70-80% of Total Cost)
Interchange is the largest component of your processing cost and the one you have the least control over. It is set by the card networks (Visa, Mastercard, Discover) and paid to the bank that issued the customer's credit or debit card. Think of it as the card-issuing bank's fee for lending money to the customer and guaranteeing the payment to you.
Interchange rates are published by Visa and Mastercard in massive tables with hundreds of rate categories. The rate for any given transaction depends on the card type (basic, rewards, corporate, prepaid), the transaction method (card-present vs card-not-present), the merchant category code (MCC) assigned to your business, and the transaction amount. For online ecommerce transactions in the United States, common interchange rates include:
Visa CPS/Card Not Present: 1.80% + $0.10 (basic consumer card, online)
Visa Signature Preferred: 2.40% + $0.10 (premium rewards card, online)
Visa Debit: 0.05% + $0.22 (regulated debit, Durbin Amendment cap)
Mastercard Core: 1.85% + $0.10 (basic consumer card, online)
Mastercard World Elite: 2.30% + $0.10 (premium rewards card, online)
The difference between a basic card and a premium rewards card is significant. When a customer pays with a no-frills debit card, your interchange cost on a $100 transaction might be $1.90. When they pay with a premium rewards credit card, it might be $2.50. The more rewards a card offers, the higher the interchange rate, because the issuing bank funds those rewards partly through higher interchange fees charged to merchants.
Assessment Fees (Card Brand Fees)
Assessment fees are charged by the card networks (Visa, Mastercard, Discover, Amex) for using their infrastructure to route and settle transactions. These fees are much smaller than interchange and are typically not itemized on flat-rate processor statements. For transparency, here are the approximate assessment rates:
Visa: 0.14% on credit transactions, 0.13% on debit transactions, plus a $0.0195 fixed acquirer network fee per transaction
Mastercard: 0.1375% for transactions under $1,000, plus a $0.0195 network access and brand usage fee per transaction
Discover: 0.13% assessment fee
American Express: varies, but Amex charges a combined interchange and assessment that is typically higher than Visa/Mastercard, ranging from 2.5% to 3.5% depending on the card and merchant category
Assessment fees add approximately $0.14 to $0.17 per $100 transaction. They are non-negotiable, but they are small enough that they rarely factor into processor selection decisions.
Processor Markup (The Only Negotiable Fee)
The processor markup is how your payment processor makes money. This is the only component of your total processing cost that you can negotiate or reduce by switching processors. The markup structure depends on the pricing model your processor uses.
On flat-rate pricing (Stripe, Square, PayPal), the markup is bundled with interchange and assessments into a single rate. Stripe's 2.9% + $0.30 includes all three components. When interchange on a specific transaction is low (such as a regulated debit card at 0.05% + $0.22), Stripe keeps the difference. When interchange is high (such as a rewards card at 2.40% + $0.10), Stripe's margin shrinks. On average, Stripe's effective markup is approximately 0.6% to 0.9% above interchange, depending on your transaction mix.
On interchange-plus pricing (Helcim, Payment Depot, merchant accounts), the markup is stated separately. A typical interchange-plus rate might be "interchange + 0.30% + $0.10," meaning you pay the actual interchange rate plus 0.30% plus 10 cents per transaction. The effective total rate varies by transaction because interchange varies, but the processor's cut is transparent and consistent.
Flat-Rate vs Interchange-Plus: Real Cost Comparison
For a $100 online transaction paid with a Visa Signature rewards card:
Flat-rate (Stripe): 2.9% + $0.30 = $3.20. Simple, predictable, same every time.
Interchange-plus (Helcim at interchange + 0.30% + $0.08): Interchange ($2.10) + Assessment ($0.14) + Markup ($0.38) = $2.62. That is $0.58 less than flat-rate.
For a $100 online transaction paid with a regulated debit card:
Flat-rate (Stripe): 2.9% + $0.30 = $3.20. Same rate as before.
Interchange-plus (Helcim): Interchange ($0.27) + Assessment ($0.13) + Markup ($0.38) = $0.78. That is $2.42 less than flat-rate.
The debit card example shows why flat-rate pricing benefits the processor when many customers pay with debit cards. Stripe collects $3.20 on a transaction where the actual interchange is only $0.27. On interchange-plus, that same transaction costs the merchant $0.78. If 30% or more of your transactions are debit cards, interchange-plus pricing can save you a substantial amount.
Why Flat-Rate Pricing Still Makes Sense for Small Businesses
Despite the math favoring interchange-plus at scale, flat-rate pricing is the right choice for most small businesses processing under $15,000 to $20,000 per month. The reasons are practical, not mathematical.
First, predictability matters when your margins are tight. You know exactly what every transaction will cost: 2.9% + $0.30. No surprises, no variation, no confusing statements. Second, flat-rate processors charge no monthly fees, no PCI compliance fees, no statement fees, and no batch fees. Those fixed costs on a traditional merchant account can add $30 to $100 per month, which eats into the per-transaction savings at low volumes. Third, the sign-up process takes minutes, not days. There is no underwriting, no credit check, and no business documentation required beyond basic identity verification.
The breakeven point where interchange-plus becomes clearly cheaper, after accounting for monthly fees and hassle, is typically around $15,000 to $25,000 per month in processing volume. Below that, the simplicity and zero fixed costs of flat-rate pricing usually win.
How to Read Your Processing Statement
If you use a flat-rate processor like Stripe or Square, your statement is straightforward: you see each transaction, the percentage fee applied, and the net deposit to your bank account. There is nothing to decode.
Interchange-plus statements are more complex. Each transaction shows the interchange category (like "VS CPS/CNP" for Visa Card Not Present), the interchange rate applied, the assessment, and the processor markup. Monthly summary sections show your total interchange costs, total assessments, and total markup. Some processors also show a blended effective rate, which is your total processing cost divided by your total sales volume.
When reviewing an interchange-plus statement, focus on the effective rate. If it is below 2.5%, you are getting a good deal. Between 2.5% and 3.0%, you are paying fair market rates. Above 3.0%, you should shop for a new processor or negotiate your markup down, because something is inflated.
Hidden Fees to Watch For
Monthly minimum fee: If your processing volume falls below a threshold (typically $25 in fees), you pay the difference. A $25 monthly minimum means you need to process at least $860 per month on a 2.9% rate to avoid the charge.
PCI non-compliance fee: Some processors charge $19 to $30 per month if you have not completed your annual PCI compliance questionnaire. This fee is entirely avoidable by completing the SAQ, which takes 15 to 30 minutes.
Chargeback fee: Most processors charge $15 to $25 per chargeback dispute, regardless of outcome. Stripe charges $15. PayPal charges $20. This fee is per dispute, so five chargebacks in a month costs $75 to $125.
Early termination fee: Some traditional merchant account providers lock you into a three-year contract with early termination fees of $200 to $500. Modern processors like Stripe, Square, and Helcim have no contracts and no termination fees. Always confirm this before signing up.
Gateway fee: If you use a separate gateway like Authorize.net on top of a merchant account, the gateway charges its own monthly fee ($25) and per-transaction fee ($0.10). This is in addition to your processing fees, not included in them.
How to Reduce Your Processing Costs
The most impactful step is matching your pricing model to your volume. If you process under $15,000 per month, stay on flat-rate. If you process over $25,000, move to interchange-plus and save $100 to $500 per month. If you are between $15,000 and $25,000, run the numbers with a few interchange-plus providers and compare.
Encourage debit card payments when possible, because debit interchange is dramatically lower than credit. Some businesses offer a small discount for debit or ACH payments. Address verification (AVS) and CVV matching can qualify your transactions for lower interchange categories by proving the cardholder is legitimate. Shipping with tracking and providing order confirmations also help qualify transactions for better interchange rates.
Surcharging, where you add a fee to credit card payments to offset processing costs, is legal in most US states but capped at 3% or the merchant's actual cost, whichever is lower. Surcharging is controversial and can reduce conversion, but some B2B businesses use it effectively. Cash discounting, where you set prices assuming card payment and offer a discount for cash or debit, is a related strategy that avoids the negative framing of a surcharge.