Most merchants don’t know their actual cost of accepting cards. Your payment processor’s advertised rate is only part of the picture — interchange fees, assessment fees, monthly fees, and batch fees all add up. This guide breaks down exactly how to calculate what you’re paying per transaction and annually, so you can compare processors accurately.
ConvesioPay uses interchange++ pricing — you see the actual cost of every transaction with no markup hidden in a flat rate. Get started →
1. The Three-Part Cost of Card Acceptance
Every card transaction has three fee layers:
- Interchange — paid to the cardholder’s bank (issuer). Varies by card type, MCC, and transaction method. Ranges from ~0.05% + $0.21 (debit) to 2.95% + $0.10 (premium rewards cards)
- Assessment fee — paid to the card network (Visa, Mastercard, Amex). ~0.14–0.15% for Visa/Mastercard credit; different rates for debit
- Processor markup — the payment processor’s revenue. Ranges from 0.10% + $0.05 (interchange-plus) to 1.5%+ bundled into flat-rate pricing
Your effective rate = Interchange + Assessment + Processor markup
2. Credit Card Fee Calculator
Step 1: Find Your Effective Rate
Your effective rate is total fees paid ÷ total volume processed. Find this on your monthly statement:
Effective Rate = Total Processing Fees ÷ Total Processing Volume × 100
Example: If you paid $420 in fees on $12,000 of volume: $420 ÷ $12,000 = 3.5%
Step 2: Calculate Cost Per Transaction
Cost per transaction = (Average Ticket × Effective Rate %) + Per-Transaction Fee
Example: $85 average ticket × 2.9% + $0.30 = $2.465 + $0.30 = $2.77 per transaction
Step 3: Calculate Annual Fees
| Processor | Rate | $100k/year volume | $250k/year volume | $500k/year volume |
|---|---|---|---|---|
| Stripe (flat rate) | 2.9% + $0.30 | $3,380 | $8,450 | $16,900 |
| PayPal (flat rate) | 3.49% + $0.49 | $4,070 | $10,175 | $20,350 |
| Square (flat rate) | 2.9% + $0.30 | $3,380 | $8,450 | $16,900 |
| ConvesioPay (interchange++) | ~1.8% avg + $0.10 | $1,900 | $4,750 | $9,500 |
Note: ConvesioPay rates are estimated averages; actual interchange varies by card mix. Interchange++ merchants save more with a higher proportion of debit transactions and non-rewards cards.
3. Common Credit Card Fee Components
| Fee Type | Who Charges It | Typical Range | Negotiable? |
|---|---|---|---|
| Interchange | Card-issuing bank | 0.05–2.95% + fixed | No (set by card networks) |
| Assessment / network fee | Visa / Mastercard | 0.13–0.15% | No |
| Processor markup | Your payment processor | 0.10–1.5%+ | Yes |
| Monthly account fee | Processor | $0–$50/month | Sometimes |
| PCI non-compliance fee | Processor | $20–$50/month | Avoid by staying compliant |
| Chargeback fee | Processor | $15–$35 per dispute | Minimize by reducing chargebacks |
| Batch/daily close fee | Processor | $0.10–$0.30/batch | Sometimes |
| Cross-border fee | Card network + processor | 0.5–1.5% | Sometimes |
4. How Interchange-Plus Pricing Saves Money
Flat-rate pricing bundles all three cost layers into one percentage, which means you’re paying the same rate regardless of whether the transaction was a cheap debit card or an expensive premium rewards card. Interchange-plus passes through the actual interchange cost and charges a separate, transparent markup.
Example: $10,000 Transaction in a Month
| Card Mix | Actual Interchange | Flat Rate Cost (2.9%) | Interchange++ Cost (~1.8%) | Savings |
|---|---|---|---|---|
| 50% debit, 50% standard credit | ~1.6% | $290 | $195 | $95 |
| 80% debit, 20% rewards credit | ~1.2% | $290 | $145 | $145 |
| 100% premium rewards | ~2.4% | $290 | $255 | $35 |
Merchants switching to interchange++ save an average of 0.38% of processing volume (ConvesioPay Q1 2026 Report). On $500,000/year of volume, that’s $1,900 saved annually.
5. How to Find Your Current Effective Rate
Your processor’s monthly statement contains all the data needed to calculate your true cost:
- Find “Total fees” or “Total charges” — this includes all fees, not just the percentage rate
- Find “Total processing volume” — the gross sales amount processed
- Divide total fees by total volume and multiply by 100 — this is your effective rate
Most merchants find their effective rate is 0.3–0.8% higher than their advertised rate once monthly fees, PCI fees, and batch fees are included.
For a detailed guide to reading your merchant statement, see Merchant Statement Analysis: How to Read and Audit Your Processing Statement. For a full breakdown of interchange fee structures, see Interchange Fee Calculator: Estimate Your True Processing Costs.
See what you’d save with ConvesioPay’s interchange++ pricing. Most WooCommerce merchants save between $1,500 and $5,000 per year compared to Stripe or PayPal flat rates. Get started →