If you’ve been researching payment processors beyond Stripe and PayPal, you’ve probably encountered “interchange++” without a clear explanation of what it actually means. This guide explains it clearly — what it is, how the three pricing models compare, who benefits from it, and at what volume the switch from flat-rate starts making real economic sense.
The Three Payment Pricing Models
| Pricing Model | What You Pay | Transparency | Best For |
| Flat Rate | 2.9% + $0.30 (all cards same) | Low — bundled | Early-stage merchants |
| Interchange Plus | Interchange + fixed markup | Medium — markup visible | Mid-market step up |
| Interchange++ ★ | Interchange + scheme fee + markup | High — all costs visible | Serious merchants at scale |
Flat Rate
One simple rate for all transactions. Stripe at 2.9% + $0.30 is the most common example. Simple and predictable — but the actual cost of processing varies enormously by card type. The flat rate averages this out in the processor’s favour.
Interchange Plus (IC+)
More transparent than flat-rate — you see the interchange cost and processor markup separately. But scheme fees may still be bundled into the processor markup.
Interchange Plus Plus (IC++)
Three components itemised separately: interchange fee (paid to issuing bank), scheme fee (paid to card network), and processor markup (the only negotiable component). You pay actual costs plus a transparent margin, nothing bundled, nothing smoothed.
Why the Distinction Matters: A Worked Example
A WooCommerce store processing $100,000/month. Card mix: 41% credit, 36% debit, 22% prepaid — the ConvesioPay Q1 2026 platform average across nearly 1 million transactions. Weighted average interchange: approximately 1.4%.
| Stripe Flat Rate | Interchange++ | |
| Rate | 2.9% + $0.30 | 1.54% + ~$0.12/txn |
| Monthly cost | ~$3,200 | ~$2,010 |
| Annual saving | ~$14,280 | |
How Interchange Rates Work
| Card Type | Approx. Interchange | Impact on IC++ |
| Basic US debit card | ~0.05% + $0.22 | Low cost ✓ |
| Standard credit card | ~1.51% + $0.10 | Moderate |
| Premium travel rewards | ~2.10% + $0.10 | Higher cost |
| Corporate purchasing card | ~2.65% + $0.10 | Highest cost |
| EU-issued cards (regulated) | ~0.2–0.3% (capped) | Low cost ✓ |
Key factors: card type (biggest variable), authentication method (3DS can reduce interchange in some categories), geography (EU cards have regulated caps), and merchant category code.
Who Benefits Most from Interchange++
- High-debit-card mix merchants. If your customers predominantly pay with basic debit, your weighted average interchange is low. Flat-rate dramatically overcharges. IC++ passes the saving through.
- High-volume merchants. The savings scale directly with volume. At $100K/month the saving is meaningful. At $1M/month it’s transformative.
Merchants with low chargeback rates. Merchants who have already reduced chargebacks through 3DS (81% reduction in Q1 2026 data) and Apple Pay get maximum benefit — total payment economics improve on both the pricing and fraud cost dimensions.
When Interchange++ Doesn’t Make Sense
- Under ~$300K annual processing volume. The saving is typically under $3,000/year — the added statement complexity may not be worth it.
- Premium-card-heavy customer base. If your customers predominantly use high-end travel rewards or corporate cards, the gap between flat-rate and IC++ narrows significantly.
- During rapid growth phases. When your card mix and volume are changing fast, flat-rate’s simplicity has value when other things are uncertain.
The Full Payments Cost Picture
The ConvesioPay Q1 2026 dataset illustrates the combined economics. The platform-wide card mix (41% credit, 36% debit, 22% prepaid) delivers meaningful IC++ savings — and those same merchants see 81% lower chargebacks from 3DS authentication and 5.8x lower dispute rates on Apple Pay.
| $20K–$40K+ | Total annual payment economics improvement at $1M volume (pricing + fraud savings combined) |
Interchange++ is one component of payment economics — not the whole picture. The total improvement combines pricing savings with fraud cost reduction from proper authentication.
ConvesioPay operates on interchange++ pricing with no minimum invoice, native WooCommerce integration, and 3DS and Apple Pay built in. The pricing transparency starts from day one, and total payment economics improve across both dimensions simultaneously.