Enter your monthly processing volume and current pricing to see how much you'd save by switching to interchange-plus.
| Cost Component | Current Processor | Interchange-Plus |
|---|
Flat-rate processors charge the same percentage regardless of card type — which means you overpay on every debit transaction. When a customer swipes a regulated debit card, the actual interchange cost is 0.05% + $0.21 (capped by the Durbin Amendment). But Square charges you 2.6% + $0.10 on that same transaction. On a $50 debit purchase, interchange costs $0.24 — Square charges $1.40. That $1.16 gap is pure markup. Multiply by hundreds of debit transactions per month, and the overpayment adds up fast.
The crossover point is around $8,000-10,000/month. Below that volume, flat-rate processors may be cheaper because interchange-plus comes with fixed monthly fees: gateway ($10-25), PCI compliance ($5-15), statement fee ($5-10), and sometimes a monthly minimum ($25). Those fees total $45-75/month. At $5,000/month in processing, the per-transaction savings on IC+ might only be $30-50/month — not enough to offset the fixed costs. Above $10,000/month, the per-transaction savings almost always outweigh the fixed fees.
Your card mix determines the size of the savings. Businesses with high debit card usage (grocery stores, gas stations, quick-service restaurants) see the biggest savings because debit interchange is dramatically lower than flat rates. Businesses with high rewards and corporate card usage (B2B services, hotels, online retail) see smaller savings because rewards interchange (1.65-2.40%) is already close to flat-rate pricing. The worst scenario for IC+ is a business where 80%+ of transactions are rewards or corporate cards — savings may be minimal or even negative.
Interchange-plus estimates use a blended IC rate based on your card mix: regulated debit at 0.05% + $0.21, standard credit at 1.65% + $0.10, and rewards/premium at 2.10% + $0.10. The processor markup is modeled at 0.25% + $0.08 (competitive market rate for $15K-50K monthly volume). Monthly fixed fees are estimated at $55/month (gateway + PCI + statement). Actual IC+ rates vary by processor — use these numbers as a baseline, then get 3 real quotes. For a deeper look at how interchange works, see our interchange guide.