Interchange-Plus Pricing Explained: How It Works and When It Saves You Money

Interchange is the wholesale cost of processing a credit-card or debit-card transaction. The card networks (Visa, Mastercard, Discover, American Express) set it; the issuing bank that issued the customer's card receives it. Every transaction has an interchange rate; that rate is non-negotiable and applies to every processor in the same way.

Interchange varies by card type. A regulated debit card runs at roughly 0.05% + $0.21 per transaction. A standard Visa credit card might run at 1.51% + $0.10. A premium rewards card can hit 2.10% + $0.10. Card-not-present transactions (online, phone, manually keyed) carry a higher interchange than card-present transactions because the network assumes more fraud risk.

Visa and Mastercard publish their interchange tables in full. They are public documents updated twice a year, and no processor can charge a merchant below interchange because the processor itself owes that amount upstream to the issuing bank. Anything a processor charges above interchange is the processor's profit.

Interchange-plus pricing is the model where the processor passes interchange through to the merchant unchanged and adds a separate, transparent markup on top. The markup is the processor's profit, expressed as a fixed percentage plus a fixed per-transaction fee. A typical interchange-plus rate looks like "interchange + 0.30% + $0.10 per transaction."

This transparency is visible line by line on the statement. The interchange charges category shows what the issuing banks were paid for processing each transaction, and a separate "discount fee" or "plus rate" line shows the processor's markup. The two together equal the merchant's total cost. Both numbers are independently verifiable; the merchant can match the interchange charges against Visa and Mastercard's published tables and confirm the processor markup against the contracted rate.

Interchange-plus is the most transparent of the three common pricing models because the math is exposed. The merchant always knows what is interchange (network cost, non-negotiable) and what is processor margin (negotiable, the lever for any cost reduction). When merchants describe their processor as charging "2.6% + 15¢" or "2.9% + 30¢," they are describing flat-rate or bundled pricing, not interchange-plus. An interchange-plus merchant cannot describe their cost with a single percentage because the percentage varies by card type on every transaction.

The three common merchant processing pricing models are bundled (also called flat-rate), tiered, and interchange-plus. The differences come down to what the merchant can see on their statement.

Bundled or flat-rate pricing charges a single rate for every transaction regardless of card type. Stripe charges 2.9% + 30¢ for online card payments. Square charges 2.6% + 15¢ for in-person tap, dip, or swipe, with manual entry at 3.5% + 15¢. The simplicity is real: predictable cost per transaction, simpler accounting. The trade-off is that flat-rate bundles interchange and processor markup into one number. The merchant cannot see how much of that 2.9% is the actual network cost and how much is the processor's margin. At higher monthly volumes the markup compounds; what looks like a small spread per transaction becomes meaningful money over thousands of transactions.

Tiered pricing sorts every transaction into "qualified," "mid-qualified," and "non-qualified" tiers, each with a different rate. The qualified rate looks low (often 1.6% + $0.10), but most transactions never qualify. The processor decides which tier each transaction lands in based on opaque internal rules, and merchants have no control over the assignment. Non-qualified rates are punitive (often 3.5% + $0.25 or higher), and processors are structurally incentivized to push transactions into higher tiers. Most tiered-pricing merchants are paying premium rates on cards that should have qualified for lower tiers.

Interchange-plus exposes the math. The merchant pays the actual interchange (which varies by card type, because that is what the network charges) plus a transparent processor markup that does not vary by card. A typical interchange-plus rate for a small or medium merchant lands around interchange + 0.20% to 0.50% + $0.05 to $0.10 per transaction. The merchant always knows what is interchange and what is profit.

Toast is a separate case. Toast bundles processing into a POS contract that does not permit third-party processing. Pay-as-you-go pays 3.09% + 15¢ on the basic tier; Core POS pays 2.49% + 15¢ with $69 per month per terminal in software cost. Restaurants cannot swap the processor while keeping the POS hardware, so a Toast restaurant cannot reach interchange-plus pricing without migrating off Toast entirely.

The break-even where interchange-plus starts winning against flat-rate is roughly $15,000 per month in card volume. Below that, the per-transaction fee on interchange-plus (typically $0.05 to $0.10 plus the markup percentage) can match or even exceed what a flat-rate processor would charge in absolute dollars, because flat-rate's per-transaction fee on a small ticket dominates the cost. Above $15K per month, the percentage markup compounds against the merchant on every transaction, and interchange-plus almost always wins, often by 0.4 to 0.8 percentage points on the effective rate.

Card mix matters. Debit-heavy merchants benefit more from interchange-plus because regulated debit interchange is much lower than credit interchange (roughly 0.05% + $0.21 versus 1.5% to 2.5% on credit). On flat-rate pricing, the merchant pays the same headline rate on every card, so the savings on debit transactions go to the processor; on interchange-plus, the savings go to the merchant. High-rewards-card merchants benefit less, because premium card interchange runs higher and eats into the spread between the bundled rate and the interchange-plus alternative.

Vertical matters too. Low-margin verticals (restaurants at 3-6% net, retail at 1-3% net) feel the savings as a meaningful margin recovery. A 0.5 percentage point reduction in processing on a 3% net-margin restaurant returns roughly 17% of net profit to the bottom line. High-margin verticals (professional services at 15-25% net) feel the same dollar savings as a smaller percentage of profit. The dollar number is the same; the impact is different.

On a true interchange-plus statement, two distinct sets of charges show up. The first is a category called "interchange charges" or "interchange fees," usually broken out by card type and transaction count. This is the wholesale cost passed through to the merchant unchanged. The second is a separate line called "discount fee," "markup," "plus rate," or "effective rate adjustment." This is the processor's margin, expressed as the percentage and per-transaction fee that the merchant negotiated. Together, the two equal the merchant's total cost.

If the statement only shows transactions sorted into "qualified," "mid-qualified," and "non-qualified" categories, with each category carrying its own blended rate, the merchant is on tiered pricing, not interchange-plus. The tier categorization itself is a sign the processor is making the assignment opaque on purpose.

If the statement shows a single blended rate (such as "2.6% on all transactions") with no breakout of interchange separately, the merchant is on flat-rate or bundled pricing. The interchange is in there, but bundled into the single rate the processor publishes.

A real interchange-plus statement looks line-itemized and somewhat overwhelming on first read. The transparency is the feature, not a bug. A merchant on interchange-plus should be able to point to a specific line and say "this is what Visa charged me, and this is what my processor charged me on top." If neither line exists separately, the pricing model is something else.

Some processors offer interchange-plus only above a volume threshold (often $50,000 per month or higher) and put smaller merchants on flat-rate by default. Other processors negotiate interchange-plus as a one-off; the rate is available but the merchant has to ask, and the burden falls on the merchant who already knows the model exists. Some processors (Square and Stripe at their consumer/standard product tiers) do not offer interchange-plus at all, regardless of volume.

In any of those cases, a merchant who wants interchange-plus pricing has to switch processors. Switching is not always the right answer. The migration has costs (POS reconfiguration, terminal replacement, customer notifications for recurring billing), and at lower monthly volumes the savings from interchange-plus may not justify those costs. The right answer depends on volume, card mix, and what the merchant is paying today.

An audit can identify whether interchange-plus would actually save the merchant money on their specific statement before any switching commitment. The savings analysis includes the migration costs and the post-switch effective rate, so the decision is grounded in dollars rather than abstract pricing model comparisons.

Several patterns come up repeatedly in conversations about interchange-plus pricing.

"Interchange-plus is only for big businesses." The threshold where it reliably saves money is roughly $15,000 per month in card volume, well within the small-business range.

"Interchange-plus rates are negotiable to anything." Interchange itself is set by Visa and Mastercard and is not negotiable. Only the processor markup is. A merchant who hears "we can get you interchange + 0.10%" should verify that interchange is being passed through unchanged, not bundled into the markup.

"A lower headline rate means lower total cost." A flat-rate at 2.4% can be more expensive in practice than "interchange + 0.40%" on a card mix dominated by regulated debit, where actual interchange runs much lower than the bundled rate. Total cost depends on card mix and markup, not the headline rate alone.

"All interchange-plus processors charge the same." The markup varies meaningfully by processor and by negotiation. The 0.20% to 0.50% range is typical for SMB; the spread inside that range is where audit work matters.