Cost Plus vs. Flat Rate Processing: Which Pricing Model is Best?

Written by

CorePro360

Published on

April 16, 2026

Read time

5 min read

By the CorePro360 Team

When selecting a payment processor, one of the most critical decisions you will make involves choosing your pricing model. The two most common structures in the industry today are Flat Rate pricing and Cost Plus pricing (often referred to as Interchange Plus).

Understanding the fundamental differences between these two models is essential for optimizing your credit card processing fees and protecting your profit margins.

What is Flat Rate Pricing?

Flat rate pricing is exactly what it sounds like: you pay a single, fixed percentage (and often a small per-transaction fee) for every credit card transaction, regardless of the card type used. This model was popularized by payment aggregators like Square, Stripe, and PayPal.

The Pros and Cons of Flat Rate

• Predictability: The primary advantage is simplicity. You always know exactly what percentage you will pay on a transaction.
• The Hidden Cost: The major downside is that you are almost always overpaying. The processor sets the flat rate high enough to cover the most expensive rewards cards. When a customer uses a cheap debit card, the processor pockets the massive difference as profit.

What is Cost Plus (Interchange Plus) Pricing?

Cost Plus, or Interchange Plus, is the most transparent pricing model available. It separates the wholesale cost of processing the card (the interchange rate set by Visa/Mastercard) from the processor's markup.

Why Cost Plus is the Industry Standard

• Total Transparency: You see exactly what the card network charges and exactly what your processor earns. There are no hidden margins.
• True Cost Savings: When a customer uses a low-cost debit card, you pay the low wholesale rate, not an artificially inflated flat rate. The savings are passed directly to you.

Which Pricing Model is Best for Your Business?

For micro-merchants, hobbyists, or businesses processing less than $5,000 to $10,000 per month, the simplicity and lack of monthly fees associated with flat-rate aggregators can be appealing.

However, once an established business consistently processes over $10,000 monthly, Cost Plus pricing is almost universally the cheaper option. The volume savings from paying true wholesale rates quickly eclipse any monthly account fees.

Frequently Asked Questions (FAQ)

What is an interchange rate?

The interchange rate is the wholesale fee set by the credit card networks (Visa, Mastercard, Discover, Amex) and paid to the bank that issued the customer's card.

Can I negotiate flat rate pricing?

Typically, no. Flat rate processors rarely negotiate their rates unless you are a massive enterprise processing tens of millions of dollars annually.

How do I know if I have Cost Plus pricing?

Look at your merchant statement. If you see dozens of different line items for various card types (e.g., "Visa Signature," "Regulated Debit"), you are likely on a Cost Plus or tiered model. If you see one single rate applied to all volume, you are on a flat rate.

Is Dual Pricing better than both?

Yes! A dual pricing program allows you to pass the processing costs to the cardholder, effectively making your processing fees zero, regardless of the underlying pricing model.

Disclaimer: The information provided in this article is for general informational and educational purposes only and does not constitute financial, legal, or professional advice. Processing rates, fees, and terms vary based on business type, transaction volume, industry classification, and other factors. CorePro360 is not a bank. Merchant services and payment processing are subject to approval. All rates and offers are subject to change without notice and are based on qualification. Please review all terms and conditions carefully before enrolling in any merchant services program. For questions specific to your business, please contact a CorePro360 representative directly.