Interchange-Plus vs. Flat-Rate Ecommerce Pricing: When to Switch

On this page 8 sections

1. Ecommerce Processing Pricing Models: How Flat-Rate Pricing Is Built
2. How Interchange-Plus Works for Online Transactions
3. Flat-Rate Processing Break-Even Math for Your Store
4. Interchange-Plus vs. Flat-Rate Ecommerce Costs by Average Order Value
5. Hidden Fees in Interchange-Plus Quotes
6. Switching Processors Without Breaking Checkout or Saved Cards
7. When to Switch From Stripe or Another Flat-Rate Provider
8. Next Steps

Key takeaways

• Flat-rate pricing bundles interchange, network fees and the provider's margin into one number. Interchange-plus shows each part separately.
• Your break-even point depends on monthly order count, average order value, card mix and the fixed monthly fees in the new quote.
• An interchange-plus quote saves money only when the markup is low and every add-on fee is disclosed in writing.
• Plan the switch around saved cards, subscriptions, refunds on old orders and your statement descriptor.

The choice between interchange-plus and flat-rate pricing for ecommerce comes down to math, not marketing. Most online stores start on a flat rate because it's simple: connect your platform, pay one percentage plus a per-order fee, and start selling. Eventually, depending on your volume, order size and the cards your customers use, that simplicity costs more than processing your transactions actually costs. This guide shows you how to find that point for your store, what to check in an interchange-plus quote, and how to switch processors without breaking checkout or losing saved cards.

All rates and dollar figures in this article are illustrative examples chosen to show the math. They are not current interchange rates or any provider's actual pricing. Use your own statements and confirm current terms with each provider.

Ecommerce Processing Pricing Models: How Flat-Rate Pricing Is Built

Every card transaction carries the same underlying costs, whatever the pricing model:

• Interchange: Paid to the card-issuing bank. The card networks set it, and it varies by card type, how the card was accepted (online vs. in person) and merchant category.
• Network (assessment) fees: Charged by Visa, Mastercard, Discover and others.
• Processor margin: What your provider keeps to cover the gateway, risk, support and profit.

A flat-rate plan averages all three into one price, such as an illustrative 2.9% + 30¢ per order. You pay that price whether the customer uses a debit card that's cheap to accept or a premium rewards card that's expensive.

For a new store with uneven volume, that averaging has real value. Your costs are predictable, you have no monthly fees to cover, and you never need to read an interchange table.

The trade-off: the provider sets that average across its whole customer base, and it includes some margin for risk. As your store grows and your card mix becomes predictable, the averaging stops working in your favor.

How Interchange-Plus Works for Online Transactions

Interchange-plus (also called cost-plus) passes interchange and network fees through at cost. The provider then adds a disclosed markup, usually a percentage plus a per-transaction fee. Your statement shows each card type at its actual cost, with the markup listed separately.

For online sellers in particular, a few points matter:

• Card-not-present interchange is generally higher than card-present, because online fraud risk is higher. Interchange-plus doesn't remove that cost. It removes only the padding on top of it.
• Card mix drives your effective rate. Regulated debit cards from large issuing banks tend to carry much lower interchange. Premium rewards and commercial cards tend to carry higher interchange.
• Fraud and data signals can matter. Address verification, CVV checks and 3-D Secure affect fraud losses and approval rates, and in some cases which interchange category applies. Ask your provider how your setup affects qualification.
• Rates change. Card networks revise interchange periodically, so your pass-through costs will move even if your markup doesn't.

To get interchange-plus pricing, you normally need your own merchant account plus a gateway rather than an all-in-one aggregator account. If you're unsure how those pieces fit together, start with our guide to setting up ecommerce payment processing.

Flat-Rate Processing Break-Even Math for Your Store

You need four inputs, all available from your current provider's dashboard or monthly statements:

1. Monthly order count (N)
2. Average order value (AOV)
3. Blended pass-through cost: Your interchange plus network fees, expressed as a percentage plus a per-order amount. A provider can estimate this from your transaction export, broken down by card brand and type.
4. The new quote: Markup percentage, markup per order, and all fixed monthly fees (F), such as gateway, account and compliance fees.

The formulas:

• Flat cost per order = flat % × AOV + flat per-order fee
• Interchange-plus cost per order = (pass-through % + markup %) × AOV + (pass-through per-order + markup per-order)
• Savings per order = flat cost − interchange-plus cost
• Break-even orders per month = F ÷ savings per order

A Worked Example (Illustrative Numbers)

Assume a store with a $60 AOV on an illustrative 2.9% + 30¢ flat plan. The interchange-plus quote has an illustrative markup of 0.30% + 10¢ and $40 a month in fixed fees.

Two lessons stand out:

• Card mix can change the answer dramatically. The same store at the same volume could save meaningfully or barely break even, depending on which cards its customers carry.
• Break-even is driven by fixed fees, not just rates. A low markup with heavy monthly fees can cost more than a slightly higher markup with no monthly fees, especially for smaller stores.

Treat break-even as a floor, not a target. If you clear it by only a few orders a month, the switching effort and risk probably aren't worth it yet. A comfortable margin above break-even, sustained for several months including your slow season, is a much stronger signal.

Interchange-Plus vs. Flat-Rate Ecommerce Costs by Average Order Value

The per-order fee is where flat-rate pricing hits small-ticket sellers hardest. Using the same illustrative flat plan:

What this means in practice:

• Low-AOV stores (accessories, digital goods, consumables) see the largest gap in percentage terms. The per-order part of any quote matters more than the percentage, so when you negotiate, push on the cents, not just the basis points.
• High-AOV stores (furniture, electronics, equipment) save more dollars per order, so they cross break-even with fewer orders. Watch the percentage markup closely, because it multiplies against every large ticket.
• Subscription stores with small recurring charges behave like low-AOV stores. They also need a careful migration plan, covered in the switching steps below.

Hidden Fees in Interchange-Plus Quotes

A low headline markup means little if the rest of the fee schedule is loaded. Ask for the full schedule in writing and check for:

• Monthly minimums: If your processing fees fall below a set amount, you pay the difference.
• Gateway fees: These can include a monthly fee plus a per-transaction fee, sometimes charged even on declined or voided transactions.
• Marked-up network fees: Network fees should pass through at cost. Some quotes add a margin or tack on vaguely named "network access" or "processing" line items.
• Account, statement and annual fees: Small individually, but they add up over a year.
• PCI compliance and non-compliance fees: Know what you pay to stay compliant and what you'd be charged if you miss a deadline.
• Chargeback and retrieval fees, plus any fees for fraud tools, address verification or 3-D Secure.
• Early termination fees and contract length: Check how long you're committed and what it costs to leave.
• "Interchange-plus" that isn't: If the statement groups transactions into qualified, mid-qualified and non-qualified buckets, that's tiered pricing, not true pass-through.

How to Negotiate Online Processing Rates

• Send recent statements and a transaction export so the quote reflects your actual card mix, not a generic assumption.
• Compare quotes on total monthly cost at your real volume, not markup alone.
• Ask the provider to disclose what changes the markup can see during the contract and how much notice they give.
• Negotiate the per-order markup if your AOV is low. Negotiate the percentage markup if it's high.
• Ask whether gateway, fraud tool and 3-D Secure fees are bundled or charged separately.

If you're comparing all-in-one providers specifically, many publish a standard flat rate and may discuss custom pricing at higher volumes. Asking your current provider is a fair first step before deciding when to switch from Stripe or a similar platform. WooCommerce sellers weighing their options can use our checklist for choosing the best payment gateway for WooCommerce.

Switching Processors Without Breaking Checkout or Saved Cards

The pricing math is the easy part. Moving processors safely is where stores get hurt. Work through these steps in order.

1. Confirm Platform Compatibility

Make sure your new gateway integrates with your storefront. MannyPay works with gateways including Authorize.net and the NMI payment gateway, and with platforms including Shopify, WooCommerce, BigCommerce and Magento.

Also check whether your ecommerce platform charges an extra transaction fee when you use a third-party processor instead of its built-in payments. That fee belongs in your break-even calculation.

2. Plan the Saved-Card Migration

Stored card tokens are typically tied to the provider that created them. Moving them usually requires a PCI-compliant data transfer between your old and new providers. Ask both sides early what's supported and how long it takes. If cards can't be migrated, plan how you'll ask returning and subscription customers to re-enter their payment details.

3. Protect Recurring Billing

Map every active subscription, its billing date and its retry logic before cutover. Ask whether the new setup supports card account updater services that keep subscribers billing when cards expire or are reissued.

4. Run the Old and New Accounts in Parallel

Keep the old account open after cutover. Refunds on past orders are generally processed through the original processor, and disputes on old transactions will still arrive there.

5. Re-Test Fraud and Approval Settings

Configure and test address verification, CVV rules and 3-D Secure authentication before going live. Settings that are too strict can cost you good orders. Watch approval rates closely in the first weeks, and if they dip, review our guide to why good customers' cards get declined at checkout. If you use Stripe, see our guide to Stripe Radar rules that stop fraud without blocking good buyers.

6. Update Your Statement Descriptor

Make sure the name on customer statements matches your store brand. An unfamiliar descriptor is a common source of "I don't recognize this charge" disputes.

When to Switch From Stripe or Another Flat-Rate Provider

Switching deserves a serious look when most of these are true:

• Your monthly volume is steady and clears break-even with room to spare, including in slow months.
• Your card mix leans toward debit or standard credit rather than premium rewards cards.
• You have a written quote with every fee disclosed and a contract term you're comfortable with.
• You have a migration plan for saved cards, subscriptions and refunds on old orders.

If only one or two apply, stay on flat rate for now and rerun the numbers as your volume grows.

Next Steps

Pull your last few monthly statements and a transaction export, then run the break-even formula with your real order count, AOV and card mix.

If you'd like a second set of eyes on the numbers, MannyPay offers merchant accounts for low-risk ecommerce stores and online payment gateway options. Request a free processing quote and include your recent statements so the comparison reflects your actual order values and card mix.

ME

About the author

MannyPay Editorial Team

Beyond the Swipe's editorial desk researches the publication's guides and news and cites its sources in every article. Articles reviewed by a named MannyPay editor carry that editor's byline.

This article is for general educational purposes and is not legal, tax or financial advice. Card network rules and state laws change; confirm current requirements for your business.