Flat rate charges one percentage on every sale. Interchange-plus charges the true network cost plus a fixed markup. Neither is always cheaper. Which one wins depends on your card mix, average ticket and how much you sell online. Test each against three months of your own statements.
Two structures
With a flat rate, you pay the same percentage on each sale, often with a small per-transaction amount. It is simple. You can predict the cost of a month with a calculator.
With interchange-plus, each sale costs what the card actually costs at the network level, plus a markup that is stated as a percentage and a per-transaction fee. Your cost varies by card.
The trade-off
A flat rate has to cover the most expensive cards, so it is priced for them. If most of your sales are low-cost debit cards, you pay for cards you do not take. Interchange-plus would pass the lower cost through.
If a large share of your sales are premium rewards cards, a flat rate may beat interchange-plus, because the flat rate averages the cost in your favor.
Why takeout changes it
A takeout-heavy restaurant has two features that matter. First, many tickets are small, so per-transaction fees weigh more. Second, online and phone orders are keyed or entered rather than tapped in person, which often costs more at the network level. If your mix leans that way, a structure that looks cheap for a counter business can look different for you.
Run the test
Take three months of statements. For each month note total card sales, number of transactions, and total fees. Compute your effective rate and your average ticket.
Then ask each provider for a written quote, and apply it to your own volume. A quote of one point five percent plus twenty cents sounds low. On a ticket of ten dollars, twenty cents is two percent by itself. The math changes with the ticket, so do it with your own numbers [VERIFY any published example you rely on].
What else to compare
Look beyond the rate: monthly fees, early termination fees, chargeback fees, equipment terms and how long a rate is fixed. A lower rate with a long lock-in may cost more than it saves.
Where Zorveta One stands
Use your own processor, or use Zorveta payments at one low cost. Contact us for pricing. Read how restaurant card processing fees work and the payments page.