Interchange Plus Pricing vs Flat Rate: Which Is Better for Your Business?

In this guide, we’ll break down these two popular pricing structures, explore their pros and cons, and help you figure out which model best fits your business needs.

What Is Interchange Plus Pricing?

Interchange plus pricing (also called “cost-plus pricing”) means you pay the actual interchange fee set by the card networks plus a fixed markup from your processor. For example, a transaction might incur a 1.8% interchange fee and a 0.3% processor markup, totaling 2.1%.

Why do businesses like this model?

• Transparency: You see exactly where your money is going.
• Fairness: Lower-risk transactions often cost less.
• Scales well as your business grows.

However, it comes with a learning curve. Your statements may have dozens of line items, especially if you accept many card types. But for high-volume or data-savvy merchants, the effort can translate to big savings.

What Is Flat Rate Pricing?

Flat rate pricing charges a single percentage on all transactions, regardless of card type or risk profile. It’s the model used by providers like Square, Stripe, and PayPal.

Why choose flat rate?

• Simple: No need to decode complex statements.
• Predictable: Great for budgeting.
• Quick to set up: Perfect for small businesses and startups.

But that simplicity can come at a cost. You might overpay on low-risk or debit card transactions where the real interchange fee is much lower than your flat rate.

Key Differences Between Interchange Plus and Flat Rate Pricing

If transparency and long-term savings are your priority, interchange plus wins. But if you just want to get up and running quickly with minimal accounting hassle, flat rate is appealing. Knowing what is payment infrastructure can help you better identify which to choose between these two.

Feature	Interchange Plus	Flat Rate
Transparency	Detailed, itemized	Bundled, simplified
Cost Control	Potential savings with high volume	Predictable costs
Complexity	Requires more effort to analyze	Easy to understand
Scalability	Ideal for growing businesses	Good for low-volume businesses
Refund Handling	Often refunds part of interchange fee	Usually doesn’t refund full fees

Pros and Cons of Interchange Plus Pricing

One of the biggest advantages of interchange plus pricing is the clear insight it provides into actual processing costs. Because fees are broken down into the interchange fee and processor markup, businesses can see exactly where their money is going. This level of transparency also opens up the opportunity to save money on low-risk transactions, such as those made with debit cards or standard credit cards. 

For companies that process a high volume of payments, the model offers greater control and the ability to optimize fees, making it a favorite among larger or more data-savvy businesses.

However, interchange plus pricing isn’t without its challenges. It can be more difficult to read and understand, especially for small businesses or those new to payment processing. Since different card types and transaction methods carry different rates, monthly fees may fluctuate depending on your customer base and payment mix. 

Additionally, it requires more internal analysis or financial expertise, which means some businesses may need a bookkeeper or accountant familiar with payment systems to make the most of this pricing model.

Pros and Cons of Flat Rate Pricing

Flat rate pricing stands out for its simplicity and ease of use. With a single, fixed percentage charged on every transaction, business owners don’t have to worry about variable card fees or deciphering complex statements. 

This makes it an ideal choice for startups, solo entrepreneurs, or small businesses that want predictable costs and minimal setup hassle. 

On the downside, this simplicity can lead to overpaying – especially on debit card payments, where the actual interchange fees are often much lower than the flat rate being charged. Businesses also lack visibility into how much of the fee goes to the card network versus the processor, making it difficult to analyze or optimize costs. 

As a company grows and its transaction volume increases, it may also find that flat rate pricing offers little room for negotiation or savings, making it less ideal in the long run.

Which Model Is Better for Your Business?

There’s no one-size-fits-all. It really depends on a few key factors:

Choose Interchange Plus If:

• You process over $10,000/month in card payments
• You want detailed reporting and cost breakdowns
• You work in a low-risk or B2B industry where savings on interchange rates are possible

Choose Flat Rate If:

• You’re a startup, solo entrepreneur, or small retail shop
• You want plug-and-play simplicity
• Your monthly volume is relatively low or unpredictable

The decision also affects your merchant agreement, which outlines how these rates are applied, and influences the overall payment processing provider relationship you’ll have.

Switching Between Pricing Models

Most businesses can switch pricing models, but timing and conditions matter. Many processors offer both models and will let you switch as you scale.

Tips for switching:

• Ask questions about hidden fees or cancellation charges.
• Run a side-by-side comparison using recent transaction data.
• Use tools or services that model potential savings.

For high-volume businesses that can handle a bit more complexity, interchange plus usually brings better long-term value. For smaller or newer businesses that prioritize simplicity, flat rate offers predictability and ease of use.

Whatever you choose, make sure it’s clearly outlined in your merchant agreement, and consider working with a transparent provider like Vellis’ payment processing services to ensure you’re getting both fair pricing and the tools you need to grow.

Frequently Asked Questions (FAQs)

What’s the main difference between interchange plus pricing vs flat rate?

Interchange plus separates fees; flat rate combines them into a single charge.

Is interchange plus pricing cheaper?

Often, yes. For businesses with high volumes or lower-risk transactions.

Why would a business choose flat rate pricing?

For simplicity, speed of setup, and predictable monthly fees.

Can I negotiate interchange plus pricing with my provider?

Yes, especially if you process large volumes or have strong finances.

How do I know which pricing model I’m currently on?

Review your monthly statements or contact your payment processor.

References

Deloitte. (2021). Payments modernization: Key considerations for pricing models. Deloitte Insights. https://www2.deloitte.com/us/en/insights/industry/financial-services/payments-modernization.html 

Mastercard. (2023). Understanding interchange rates and fees. Mastercard. https://www.mastercard.us/en-us/about-mastercard/what-we-do/interchange.html The Strawhecker Group. (2022). The guide to payment processing pricing models. https://www.tsgpayments.com/knowledge-base/the-guide-to-payment-processing-pricing-models/