What Are You Really Paying in Credit Card Processing Fees?

Understanding Credit Card Processing Fees:
Interchange, Assessments, and How Payments Actually Work

If you’ve ever reviewed your merchant statement and seen terms like “interchange,” “network assessments,” or “dues,” you’re not alone. The payments industry uses language that isn’t always intuitive.

At a high level, every credit card transaction involves multiple financial institutions. Each one plays a role. Each one collects a small fee.

Understanding how credit card processing works is the first step toward understanding what you’re paying and why:

How a Credit Card Transaction Works

Every time a customer taps, inserts, or enters their card, a chain of events happens in just a few seconds.

Here’s the simplified flow:

Customer
→ Your Business (POS or Website)
→ Payment Gateway / Processor
→ Acquiring Bank (your merchant bank)
→ Card Network (Visa, Mastercard, etc.)
→ Issuing Bank (the customer’s bank)
→ Approval travels back the same way

The issuing bank approves or declines the transaction. If approved, funds are settled to your merchant account, typically within one to two business days.

This process is standardized across the industry. What changes is how pricing is structured around it.

  What Is an Interchange Fee?

Interchange is the largest component of your credit card processing fees. It is paid to the issuing bank-- the bank that issued your customer’s credit card. The bank takes on fraud risk, provides the card to the consumer, and funds rewards programs. Interchange compensates them for that role.

Interchange rates vary depending on:

• Debit vs credit card
• Rewards vs non-rewards card
• In-person vs online transaction
• Your industry classification

Interchange is not set by your processor. It is established by the card networks and applies universally. Every processor pays the same base interchange rates.

What Are Assessments and Network Dues?

In addition to interchange, card networks like Visa and Mastercard charge assessments (sometimes called dues). These are smaller fees that support the infrastructure of the payment networks. They are also standardized and non-negotiable. So when you see interchange and assessments on your merchant statement, those fees are not the processor’s markup. They are part of the underlying payment ecosystem.

Where Pricing Models Matter

After interchange and network fees, the remaining portion of your processing cost is the processor’s markup. This is where pricing structures differ. In a flat-rate model, interchange and assessments are bundled together and averaged into one rate. You pay the same percentage regardless of the actual cost of the card used.

In an interchange-plus model, those wholesale costs are passed through directly, and the processor adds a transparent markup.

The total amount you pay depends on:

• Your card mix
• Your transaction volume
• Your industry risk profile
• Your pricing model

This is why two businesses both “paying 2.9%” may have very different underlying cost structures.

Why This Matters

Credit card processing fees are often one of the top operating expenses for growing businesses. Understanding interchange fees and how credit card processing works gives you clarity around:

• What is fixed
• What is negotiable
• What can be optimized

Interchange and assessments are built into the system. Your pricing structure is not.

At OnCore Payment Technologies, we believe business/es should understand the mechanics behind what they’re paying. When you understand the flow of a transaction and the components of processing fees, reviewing your merchant statement becomes far less confusing. Clarity leads to better decisions --and better decisions protect margin.