Interchange Plus vs. Flat Rate Calculator
Enter your monthly volume, average ticket, and card mix to see an estimated cost comparison between flat-rate and interchange-plus pricing — plus how your current effective rate stacks up.
Calculator
Total card transactions per month in dollars
Average transaction size; used to calculate transaction count
Credit cards (% of volume)
Debit cards (auto)
Total monthly fees ÷ total monthly volume × 100. Find this on your statement or leave as-is to compare flat rate.
Assumptions: flat rate = 2.9% + $0.10/txn; interchange-plus = blended interchange (credit avg 1.7%, debit avg 0.5%) + 0.25% GoPayhawk margin + $0.10/txn. Consistent with the GoPayhawk vs. Stripe analysis. Results are estimates only.
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Why your pricing model is the biggest fee lever you have
Most small and mid-size businesses sign up with Square, Stripe, or PayPal and pay a flat rate — 2.7%, 2.9%, maybe 3.5% — on every card transaction without thinking much about it. That flat rate is convenient, but it hides the real cost structure of card processing.
Every time a card is swiped, the processor pays an interchange fee to the card-issuing bank. That fee varies by card type: regulated debit cards issued by large banks cost roughly $0.21 + 0.05% per transaction under the Durbin Amendment. A basic Visa credit card runs about 1.51%. A premium rewards card can exceed 2.30%. These rates are set by the card networks twice per year and are the same for every processor in the country.
With flat rate, your processor charges you one blended rate and pockets the difference. With interchange-plus, you pay the actual interchange cost for each transaction plus a fixed margin. When your customer pays with a debit card, you pay debit interchange (low). When they pay with a rewards card, you pay rewards interchange (higher) — but you still don't overpay on every other transaction to subsidize the expensive ones.
How the math works at $30,000/month
Take a business with $30,000 in monthly card volume and a $75 average ticket. That's roughly 400 transactions per month. If 70% of volume is credit and 30% is debit:
- Flat rate (2.9% + $0.10): $30,000 x 0.029 = $870, plus 400 x $0.10 = $40. Total: approximately $910/month.
- Interchange-plus: Credit interchange avg ~1.7% on $21,000 = $357; debit interchange avg ~0.5% on $9,000 = $45; GoPayhawk margin 0.25% on $30,000 = $75; plus 400 x $0.10 = $40. Total: approximately $517/month.
- Savings: approximately $393/month, or $4,716/year.
Your actual results will vary depending on your exact card mix, average ticket, and GoPayhawk margin, which is quoted individually. A free statement analysis shows you your real interchange-plus rate versus what you are currently paying.
Interchange vs. Flat Rate FAQ
Flat rate blends the card network cost and the processor's margin into one percentage. Interchange-plus separates the two: you pay the actual card network rate plus a fixed margin. With flat rate, you pay the same percentage whether your customer uses a low-cost debit card or a high-cost rewards card. With interchange-plus, costs reflect the actual transaction type.
For most businesses processing more than $5,000 to $10,000 per month, interchange-plus is cheaper — typically by 0.3% to 1.0% of volume. The savings are largest when you have meaningful debit card volume or when your current flat rate is 2.7% or higher. At very low volumes the per-transaction cost can offset the rate advantage.
Interchange rates range from about 0.05% + $0.21 for regulated debit up to 2.5% or more for premium rewards cards. The 1.7% used in this calculator is a rough blended average for a typical business credit card mix. Your actual blended rate shows on your monthly statement if you are on interchange-plus pricing.
For retail and restaurant businesses, a competitive interchange-plus effective rate is roughly 1.8% to 2.4%. E-commerce typically runs 2.2% to 2.8% due to higher card-not-present interchange. B2B merchants processing corporate cards with Level 2/3 data can often get below 2.0%. If your current effective rate is above 3.0%, you are very likely paying more than necessary.
Divide total monthly processing fees (all fees including monthly and per-transaction) by total monthly volume, then multiply by 100. For example: $600 in fees on $25,000 volume = 2.4% effective rate. GoPayhawk will calculate this for you as part of a free statement analysis — just upload or email your current statement.
Flat rate works best for very low volume businesses (under $5,000/month) or pop-up shops where simplicity outweighs cost optimization. It is also common with payment facilitators like Square and Stripe, which offer easy setup at the cost of higher fees. If you are processing more than $10,000/month and have not compared pricing models, you are likely overpaying.
Any card linked directly to a checking or savings account is a debit card. Cards from banks with more than $10 billion in assets carry regulated debit interchange capped under the Durbin Amendment at $0.21 + 0.05%. PIN debit is the cheapest transaction type. Credit cards, prepaid cards, and debit cards from smaller banks carry different interchange categories. Your processor statement itemizes volume by card category on interchange-plus pricing.
Some processors offer both models; others only offer flat rate (Square and Stripe are flat-rate-only). Switching to GoPayhawk on interchange-plus typically takes a few business days. GoPayhawk operates month-to-month — no annual contracts. A free statement analysis shows your potential savings before you sign anything.
Get Your Exact Interchange-Plus Rate
The calculator gives you an estimate. A free statement analysis gives you your actual rate, compared line-by-line against what you're currently paying.
