Educational Guide
Most merchants only see a single number on their monthly processing statement — but that rate is actually made up of multiple fee layers from different parties. Understanding how payment processing fees work helps you evaluate costs accurately and ask better questions when comparing processors.
Last updated: June 17, 2026
Quick Answer
Payment processing fees are made up of three components: interchange (paid to the card-issuing bank), assessment fees (paid to the card network), and the processor's markup. Only the processor markup varies between providers — interchange and assessment fees are non-negotiable. Your effective rate — total fees divided by total volume — is the most accurate way to compare processor costs.
When a customer pays by card, three separate entities typically receive a portion of the processing fee: the card-issuing bank (interchange), the card network (assessment fees), and the payment processor (markup). Processors pass on the first two costs and add their own on top.
This is why total processing cost is often described as interchange + assessment + processor markup. Only the processor markup is negotiable; interchange and assessment fees are set by card networks and apply equally to all processors.
Interchange is the fee paid to the card-issuing bank on each transaction. It is the largest component of total processing cost, typically representing 1.5%–2.5% of a transaction for consumer credit cards, and lower for debit cards.
Interchange rates vary by card type, transaction method, and merchant category. Rewards credit cards carry higher interchange rates because the issuing bank uses interchange to fund cardholder rewards. Debit cards carry lower interchange rates. In-person card-present transactions qualify for lower interchange than online (card-not-present) transactions.
Interchange tables are published by Visa and Mastercard and updated twice a year (April and October). Understanding interchange helps merchants evaluate which pricing model — flat rate, interchange-plus, or membership — is most cost-effective for their card mix.
Note: Interchange rates are set by card networks, not by your payment processor. No processor can offer you rates below interchange for the same transaction type.
Assessment fees (also called card brand fees or network fees) are charged by the card network itself — Visa, Mastercard, Discover, or Amex — on each transaction. They are typically much smaller than interchange, usually under 0.15% per transaction.
Like interchange, assessment fees are non-negotiable and apply equally to all processors. In a flat-rate model, these fees are absorbed into the overall rate. In interchange-plus and membership pricing, they are typically listed as separate line items on your statement.
The processor markup is the fee that your payment processor charges on top of interchange and assessment fees. This is the only portion of processing cost that is negotiable and that varies between processors.
In flat-rate pricing, the markup is embedded in the overall rate — you do not see interchange and assessment separately. In interchange-plus pricing, the markup is clearly listed as the 'plus' component. In membership pricing, the monthly fee replaces the percentage markup.
Processor markups vary significantly between providers and pricing models. When comparing processors, focus on the total effective cost rather than the headline markup rate alone.
Beyond the per-transaction rate, processors may charge a range of additional fees. These can meaningfully affect total processing cost and should be reviewed carefully before signing any agreement.
Note: Always request a complete fee schedule before signing up with a processor. Compare total monthly cost — not just the processing rate.
Your effective rate is the most useful number for comparing processors across different pricing models. It is calculated by dividing total processing fees by total processing volume for a given period.
For example: if you processed $20,000 in a month and paid $520 in total fees (including all monthly fees, per-transaction fees, and processing rate charges), your effective rate is 520 / 20,000 = 2.6%. This single number reflects the true total cost of processing — regardless of pricing model.
To calculate your effective rate from a current processor statement, add up all fees on the statement (processing charges, monthly fees, PCI fees, etc.) and divide by total volume.
These are the most common errors merchants make when evaluating and managing processing fees:
Use this checklist to evaluate and reduce your payment processing fees:
Interchange rates are set by card networks (Visa, Mastercard, Discover, American Express) — not by payment processors. Rates are published publicly and updated twice a year. No processor can offer interchange rates below the card network's published rates for the same transaction type.
If you use interchange-plus pricing, your fees vary because interchange rates differ by card type. Months with more rewards credit card usage will have higher average interchange costs than months with more debit card usage. Flat-rate pricing produces more predictable monthly costs.
A PCI compliance fee is charged by some processors to assist with or maintain PCI DSS compliance. PCI DSS (Payment Card Industry Data Security Standard) is a set of security requirements for businesses that handle cardholder data. Most processors require annual completion of a self-assessment questionnaire.
Effective rates for small businesses typically range from 2%–3.5% of volume, depending on card mix, transaction channel, and pricing model. In-person businesses with a high debit card ratio tend to have lower effective rates; online businesses with premium reward card usage tend to have higher rates. Always compare total effective cost, not just the headline rate.
Use Fit Check to identify providers that may deserve closer research based on your business profile, or open the Cost Calculator to estimate your fees.