Most WooCommerce stores are on flat-rate pricing. They pay Stripe 2.9% + $0.30 per transaction or a similar blended rate, regardless of what type of card the customer uses. That simplicity is convenient at low volume. At scale, it’s expensive.
Interchange++ pricing, the model that enterprise merchants use, passes the actual interchange cost through to the merchant rather than bundling it into a blended rate. For merchants with the right card mix and volume, it’s consistently cheaper than flat-rate. Often significantly so.
The Three Components of Every Card Transaction Fee
Every card transaction involves three fee components:
| Card Type | Approximate Interchange |
| Basic US debit card | ~0.05% + $0.22 |
| Standard Visa credit card | ~1.51% + $0.10 |
| Premium travel rewards card | ~2.10% + $0.10 |
| Corporate purchasing card | ~2.65% + $0.10 |
Interchange (paid to issuing bank): Largest component, set by Visa/Mastercard, varies by card type as shown above.
Scheme fee (paid to card network): ~0.14% for Visa. Non-negotiable, same for all processors.
Processor markup: The only component that varies between processors and can be negotiated.
On flat-rate pricing, all three components are bundled. You pay the same regardless of card type. On interchange++, you pay actual costs — and benefit when customers pay with lower-interchange cards.
Why Flat-Rate Becomes Expensive at Scale
The ConvesioPay Q1 2026 dataset shows a platform-wide funding mix of 41% credit, 36% debit, and 22% prepaid across nearly 1 million transactions.
| 41% credit / 36% debit / 22% prepaid | Platform funding mix — ConvesioPay Q1 2026 |
For a merchant with that mix, weighted average interchange is approximately 1.3–1.5%. On Stripe at 2.9%, the processor captures ~1.1–1.4% above actual interchange costs. On interchange++ at a competitive processor margin of ~0.35%, the effective rate is ~1.75% — a difference of approximately 1.1% in effective processing rate.
On $1M of annual card volume, that difference is $11,000 per year. On $2M, it’s $22,000.
Interchange++ Savings at Different Volume Levels
| Annual Volume | Flat Rate (2.9% + $0.30) | Interchange++ (~2.0%) | Annual Saving |
| $250,000 | ~$7,750 | ~$5,000 | ~$2,750 |
| $500,000 | ~$15,250 | ~$10,000 | ~$5,250 |
| $1,000,000 | ~$30,250 | ~$20,000 | ~$10,250 |
| $2,000,000 | ~$60,250 | ~$40,000 | ~$20,250 |
| $5,000,000 | ~$150,250 | ~$100,000 | ~$50,250 |
Figures are illustrative estimates based on typical mid-market card mix. The breakeven point, where savings materially exceed switching costs — is typically $500K–$1M in annual processing volume.
How to Evaluate Whether Interchange++ Is Right for Your Store
- Pull your current card mix. Most processors provide a breakdown by card type in reporting. Request it explicitly if not visible.
- Calculate your current effective rate. Total fees ÷ total volume for the last 3 months — including dispute fees and monthly fees.
- Model your interchange++ rate. Use published Visa/Mastercard interchange schedules + a processor margin of ~0.3–0.5% to estimate your effective rate.
Compare at your annual volume. If the saving exceeds $5,000–$10,000 annually, the case for switching is clear.
What to Look for in a WooCommerce Interchange++ Processor
- Genuine transparency. You should see interchange cost, scheme fees, and processor margin as separate line items.
- Competitive processor margin. Typically 0.20%–0.50% plus a small per-transaction fee for mid-market WooCommerce merchants.
- No minimum invoice. Some processors (including Adyen direct) require a minimum invoice that eliminates savings for lower-volume merchants. ConvesioPay has no minimum invoice.
- Native WooCommerce integration. A well-maintained plugin reduces operational overhead and integration risk.
3DS and fraud controls included. The total cost of payments includes chargeback costs. A processor with proper 3DS routing — delivering the 81% chargeback reduction from Q1 2026 data — improves total economics beyond pricing savings alone.
The Bottom Line
Interchange++ pricing isn’t complicated — it’s just transparent. You pay what card processing actually costs, plus a disclosed processor margin, rather than a blended rate that subsidizes the processor on low-interchange transactions.
For WooCommerce stores processing $500K+ annually, the savings are typically material: $5,000–$20,000+ per year depending on volume and card mix — before accounting for chargeback cost improvements from proper fraud controls.
| 81% | chargeback reduction with 3DS active — ConvesioPay Q1 2026 (adds to pricing savings) |
ConvesioPay offers interchange++ pricing with no minimum invoice, native WooCommerce integration, and 3DS and Apple Pay built in. The savings start from the first transaction.