Interchange
$0.00
0.00%
Assessment
$0.00
0.00%
Effective Rate
0.00%
interchange + assessment
Interchange rate
Interchange (% portion)
Interchange (per-txn portion)
Network assessment fee
Per-transaction fee
Total cost (before processor markup)
If you process $10,000/month at this rate
$0
estimated annual interchange + assessment cost (before processor markup)

The hidden math behind every card swipe

When a customer pays $100 with a Visa rewards card, about $2.10 leaves your bank account before your processor takes a cent. That money splits three ways: roughly $1.75 to the bank that issued the card (interchange), $0.14 to Visa (assessment), and $0.21 in fixed per-transaction fees. Your processor's markup comes on top of all that.

This three-layer structure is why processing statements are so confusing. Processors who advertise "2.9% + $0.30" are bundling all three layers plus their profit into a single number. That simplicity comes at a cost: bundled pricing hides the fact that a debit card transaction costs roughly a third of a rewards card transaction, but you pay the same rate for both.

Interchange-plus pricing exposes these layers separately. The interchange passes through at cost, and you only negotiate the "plus" portion. For a business processing $20,000/month, the difference between bundled and interchange-plus pricing is typically $80-$160/month, because bundled processors pocket the spread on every debit transaction.

Why card type matters more than card network

Merchants obsess over Amex's reputation for high fees, but the gap between a Visa rewards card and a Visa debit card is larger than the gap between Visa and Amex on the same card type. A regulated debit transaction costs 0.05% + $0.21 regardless of network. A Visa Signature rewards card costs 2.10% + $0.10. That is a 40x difference in the percentage component on the same network.

The practical implication: your card mix matters more than which networks you accept. A restaurant where 70% of transactions are debit cards will pay dramatically less in interchange than an online SaaS company where 90% of charges hit rewards and corporate cards, even if both process the same dollar volume.

The Durbin Amendment divide

Regulated debit interchange (banks with $10B+ in assets) is capped at 0.05% + $0.21 by federal law. But exempt debit (small banks, credit unions) is not capped and typically runs 0.80-1.15%. You cannot control which debit cards your customers carry, but you can monitor your statement to see the actual split. If more than 30% of your debit volume is exempt, your effective debit rate may be double what you expected.

Card-present vs. card-not-present: the fraud premium

Every rate table has two tiers: card-present (CP) and card-not-present (CNP). The CNP premium of 0.10-0.15% exists because online transactions have roughly 2-3x the chargeback rate of in-person transactions. This isn't arbitrary — it reflects the issuing bank's actual fraud loss exposure.

Keyed-in transactions sit even higher than standard CNP because they lack the anti-fraud signals that both chip readers and 3D Secure provide. A keyed-in Visa rewards transaction runs approximately 2.40% + $0.10, compared to 1.95% + $0.10 for the same card tapped at a terminal. On $50,000/month in volume, that 0.45% difference costs $2,700 per year.

If your staff regularly keys in card numbers instead of using the terminal, fixing that single behavior change can save more than negotiating your processor's markup down.

What processors add on top

The rates in this calculator cover interchange + assessment only. Your processor adds their markup on top, which is the only negotiable portion of your processing cost. Typical markups by pricing model:

Interchange-plus (most transparent)

Markup of 0.10-0.50% + $0.05-$0.10 per transaction, depending on volume. A business processing $30,000/month can typically negotiate 0.15-0.25% + $0.07. This model lets you see exactly what goes to interchange and what goes to your processor.

Flat-rate (simplest)

Stripe, Square, and Shopify charge 2.6-2.9% + $0.10-$0.30 regardless of card type. The processor pockets the spread between this flat rate and actual interchange. This model overpays on debit, underpays on corporate cards, and averages out — but usually in the processor's favor by 0.30-0.60%.

Membership/subscription (lowest for high volume)

Stax, Payment Depot, and similar charge a monthly fee ($49-$199) and pass interchange through at cost with a small per-transaction fee. This wins when volume exceeds roughly $8,000-$15,000/month, because the fixed monthly fee replaces the percentage markup.

Frequently asked questions

What is an interchange fee?
An interchange fee is the transaction fee that a merchant's bank (acquirer) pays to the cardholder's bank (issuer) every time a credit or debit card is used. It typically ranges from 0.05% + $0.21 for regulated debit to 3.50% for premium corporate Amex cards. Interchange is the largest component of processing costs, usually accounting for 70-90% of total fees.
Why are interchange fees different for each card type?
Card networks set interchange rates based on the issuing bank's risk and reward costs. Rewards cards have higher interchange because the bank funds cashback and points from interchange revenue. Corporate cards carry higher fraud and default risk. Debit cards have lower rates partly due to the Durbin Amendment, which caps regulated debit interchange at 0.05% + $0.21.
What is the difference between interchange and the total processing fee?
Interchange goes to the card-issuing bank. On top of interchange, you also pay assessment fees to the card network (Visa, Mastercard, etc.) and a processor markup to your payment processor. The total of all three is your effective processing rate. Interchange is non-negotiable, but the processor markup is.
Do card-not-present transactions cost more?
Yes. Card-not-present (online, phone, keyed-in) transactions have higher interchange rates than card-present (swiped, dipped, tapped) transactions. The premium is typically 0.10-0.15% because remote transactions have higher fraud rates. This is why e-commerce merchants generally pay more than brick-and-mortar stores.
Can merchants negotiate interchange fees?
No. Interchange rates are set by card networks and apply uniformly to all merchants. What you can negotiate is your processor's markup on top of interchange. On interchange-plus pricing, the interchange passes through at cost and only the "plus" portion is negotiable.