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.
How Interchange Rates Work
| Card Type | Approx. Interchange | Impact on IC++ |
| Basic US debit card | ~0.05% + $0.22 | Low cost ✓ |
| Standard credit card | ~1.80% + $0.10 | Moderate |
| Premium travel rewards | ~2.70% + $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 (up to 81% lower chargeback rates — a 5.1x improvement, per 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.
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 runs on a flat 2.9% + $0.30 with no monthly fees and no minimum invoice — native WooCommerce integration and 3DS/Apple Pay built in. If your volume and card mix favor interchange++ instead, that’s a legitimate reason to look elsewhere, and this guide should have helped you figure out which side of that line you’re on.