The short answer
A US debit card carries two logical capabilities: the Visa/Mastercard signature-debit rail (what shows up as "credit" on a terminal prompt) and the PIN-debit rail that routes through a regional debit network like STAR, NYCE, Pulse, Accel, or Shazam. PIN debit requires the customer to enter a PIN and clears on the debit network; signature debit uses a signature or no verification at all and clears on the card-brand network. Same card, two very different settlement paths, two very different cost structures.
How they actually differ
- Authentication. PIN debit requires PIN entry on a PCI-certified PIN pad. Signature debit requires a signature (or nothing at all on small tickets / online).
- Network. PIN debit clears on a debit network (STAR, Pulse, NYCE, etc.). Signature debit clears on Visa or Mastercard.
- Interchange. Post-Durbin regulated debit caps both at 0.05% + $0.21, but PIN debit often clears even cheaper on the specific debit network's rate table. Unregulated debit (small issuing banks under $10B in assets) can run higher on signature than on PIN.
- Settlement speed. PIN debit often settles T+0 or T+1 — real money in your account fast. Signature debit settles T+2 like a credit card.
- Chargeback liability. PIN-authenticated transactions are much harder for customers to dispute successfully. Signature debit carries the usual CNP liability rules if keyed online.
- Channel. PIN debit requires a physical PIN pad. It is not available online. All e-commerce debit runs as signature debit.
When merchants care
- Retail + card-present. PIN debit can save you real basis points on debit-heavy volume. A grocery store or gas station running 60% debit will see measurable effective-rate drops from pushing customers to PIN.
- Small unregulated banks. If your customers use credit-union debit cards or small community-bank debit cards, PIN routing may clear 30-80 bps cheaper than signature.
- Fast cash-flow needs. PIN debit can settle same-day on some processors. If you're thin on working capital, it's a free tool to pull settlement forward.
What multi-brand e-commerce operators need to know
- You probably run zero PIN debit. If all your brands are online, every debit transaction you see is signature debit — no PIN pad involved.
- Durbin-capped debit is still cheap. Even on signature, a regulated-bank debit transaction is 0.05% + $0.21 in interchange. Don't let a flat-rate processor quote you 2.9% on debit without understanding how much margin they're keeping. See Durbin Amendment.
- Interchange-plus preserves the debit savings. Flat-rate charges the same price on debit as on credit. Interchange-plus passes the debit savings through to you.
- Debit-heavy mix is a negotiation lever. If your portfolio runs 25%+ debit, your acquirer should be quoting more aggressive markup because their pass-through cost is lower.
Why this shows up in multi-brand conversations
When multiflow models your consolidated effective rate, we separate debit from credit volume and price each accordingly. Four brands that are collectively 35% debit look very different on an interchange-plus quote than they would on a flat-rate quote — and the savings from routing the debit efficiently usually more than covers the orchestration fee on the credit side. See Durbin Amendment and our interchange calculator.