Credit Card Processing Fee Calculator
Processing fees are one of the quietest costs in any business - often invisible until you add them up. Enter your monthly card volume below to see exactly what you're paying, and whether a different pricing model would cost less.
Example: a service business on flat-rate pricing
$18,000/mo in card sales at an average ticket of $150 (120 transactions) on flat-rate pricing at 2.9% + $0.30 comes out to $558/month in fees (3% of volume). At a typical interchange-plus rate, the same volume would cost roughly $336/month instead - a $222/month difference at this volume. Enter your own numbers above to see your real comparison.
Methodology
Total monthly cost = (monthly volume × your rate) + (transaction count × your per-transaction fee) + a monthly subscription fee if you're on a subscription model. Transaction count is estimated as monthly volume divided by average transaction size. The comparison table shows this same formula applied to your two other pricing models using typical published rates, since we don't know your actual rate under a model you aren't using.
Data source: commonly published rate ranges for flat-rate, interchange-plus, and subscription processors. Last reviewed: September 2026. Real rates vary by processor, industry, card-present vs. card-not-present transactions, and negotiated terms - this is a directional comparison tool, not a quote.
See our full calculation methodology for every calculator's exact formula and data sources.
Frequently asked questions
What's the difference between flat-rate and interchange-plus pricing?
Flat-rate charges one predictable percentage plus a small fee on every transaction, regardless of card type - simple, but it bakes in a margin on every sale. Interchange-plus passes through the card network's actual interchange rate (which varies by card type and transaction) plus a fixed markup, so it's usually cheaper at higher volume but less predictable transaction-to-transaction.
Why do processing rates vary by industry or card type?
Card networks set different interchange rates based on perceived risk and how the card is used - a rewards credit card typically costs more to process than a debit card, and card-not-present transactions (online, phone) generally cost more than card-present ones because of higher fraud risk. Your effective blended rate reflects the mix of cards and transaction types your specific business sees.
Is a subscription-based processor (like Payment Depot or Stax) actually cheaper?
It can be at high volume - subscription processors charge a flat monthly membership fee in exchange for passing through interchange at close to cost, which only pays for itself once your transaction volume is high enough that the savings on rate exceed the membership fee. At low volume, the fixed monthly cost usually isn't worth it.
How do Square, Stripe, and PayPal's rates compare to a traditional merchant account?
Square, Stripe, and PayPal typically use flat-rate pricing - simple and fast to set up, with no monthly minimums, which is why they're popular for smaller or newer businesses. A traditional merchant account with interchange-plus pricing usually becomes cheaper once volume is high enough, at the cost of more setup and sometimes a monthly minimum or contract.
How is this different from the Shopify Profit Margin Calculator?
The Shopify calculator bakes in Shopify Payments' specific rate as one input among several. Use this calculator when you want to isolate and compare processing costs on their own, across any platform - not just Shopify.
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