Flat Rate vs Interchange-Plus vs Tiered Pricing: Which Is Cheaper?
Compare flat-rate, interchange-plus and tiered card processing pricing, with a break-even example and guidance on which model fits your volume and ticket size.
Flat-rate pricing is cheapest for most new and low-volume businesses because it is simple and has few extra fees. Interchange-plus tends to win once you process steady, higher volume or larger tickets, because you pay the real cost of each card plus a fixed markup. Tiered pricing is rarely the best deal because the rules for which transaction lands in which bucket are set by the provider. The right answer for you depends on your average ticket, card mix and monthly volume, and you can find it with a few lines of arithmetic.
How each model works
Flat rate. You pay a single percentage plus a fixed fee for each transaction, such as a percentage in the high twos plus 30 cents for online cards. Interchange, assessments and the provider's margin are all folded in. The provider keeps the difference between its blended price and the actual cost, so on low-cost cards it earns more and on high-cost cards less.
Interchange-plus (also called cost-plus). The statement shows the true interchange and network assessments for every transaction, and the provider adds a markup, written like "interchange + 0.4% + $0.10". You see exactly what each card cost.
Tiered. The provider sorts transactions into "qualified", "mid-qualified" and "non-qualified" buckets and charges a different rate for each. Which bucket a card falls into depends on rules defined by the provider, such as rewards card or keyed entry. Because the bucket assignments are controlled by the provider, you cannot easily check whether a rate is fair.
Side-by-side comparison
| Feature | Flat rate | Interchange-plus | Tiered |
|---|---|---|---|
| Predictability | High | Medium | Low |
| Transparency | Medium (one rate, no breakdown) | High | Low |
| Best for | Low volume, small teams, fast start | Steady volume, larger tickets | Seldom a first choice |
| Typical extras | Fewer; may hold funds | Monthly fee, PCI fee, minimums | Statement fee, non-qualified surcharges |
| Switching difficulty | Easy | May involve contract terms | Often long contracts |
A break-even example with illustrative numbers
Assume a merchant processes 500 online transactions a month with a $60 average ticket, or $30,000 in sales.
- Flat rate of 2.9% + $0.30: 30,000 x 0.029 = $870, plus 500 x 0.30 = $150, total $1,020, effective rate 3.40%.
- Interchange-plus with an assumed average interchange and assessments of 2.1% + $0.10 on this card mix, plus a markup of 0.4% + $0.10, plus a $25 monthly fee. Percentage part: 2.5% of $30,000 = $750. Fixed part: $0.20 x 500 = $100. Total with monthly fee: $875, effective rate 2.92%.
Savings in this scenario: $145 a month, or $1,740 a year. The interchange figures are assumed for illustration; your real average depends on your cards, so use your statements.
Now try a merchant with $3,000 a month in sales across 50 transactions. Flat: 2.9% of $3,000 is $87 plus $15 = $102. Interchange-plus: 2.5% of $3,000 is $75 plus $10 = $85, plus a $25 monthly fee = $110. At this size the flat plan is cheaper, because the fixed monthly fee dominates. That is why small merchants often do best with flat rate and revisit the question as volume grows.
Plug your own numbers into the fee calculator to see where the break-even point falls for you.
The break-even rule of thumb
A simple way to think about it: interchange-plus adds a monthly overhead but reduces the per-dollar cost. The break-even monthly volume is roughly the monthly overhead divided by the percentage saving. If interchange-plus saves 0.4 percentage points on the percentage side and the extra monthly fees are $25, break-even is about $25 / 0.004 = $6,250 in monthly sales, before considering the fixed per-transaction differences. Above that, interchange-plus likely wins on the percentage side; below it, flat rate probably does. This is a rough guide, not a rule, and the per-transaction fees can shift the answer.
Pitfalls specific to each model
- Flat rate: extra charges for international cards, currency conversion, disputes, and instant payouts may not be in the headline rate. Providers may also limit negotiating room. Check the policy for holds and reserves.
- Interchange-plus: watch for large "junk" fees buried in the statement, such as annual fees, monthly minimums and batch fees. Ask whether the markup is applied to interchange only or also to network assessments.
- Tiered: ask for the written definition of each tier and the percentage of your transactions that typically land in each. If the provider cannot say, treat that as a warning.
Hybrid and subscription models
Some providers offer a membership model: a monthly fee in exchange for a very small markup over interchange. These can be the cheapest option for merchants with high, consistent volume, but they are worse than flat rate for low volume because you pay the subscription regardless. Compare using total annual cost, not the markup.
Questions to ask any provider
- Is the quote flat rate, interchange-plus or tiered?
- What is the markup, per-transaction fee and every monthly or annual fee?
- Are there fees for refunds, chargebacks, international cards or batch settlements?
- How long is the contract, and what is the early termination fee?
- Can the provider raise rates, and with how much notice?
- Is there a reserve or holdback, and under what conditions?
For a wider list of fees, see Hidden Fees in a Merchant Agreement, and for negotiation tips read How to Lower Your Payment Processing Fees.
When to consult a professional
If you process large volume or have multiple locations, an independent statement analysis by an accountant or consultant who is not paid by the processor can be valuable. Avoid reviewers who earn commission from the provider they recommend.
FAQ
Is interchange-plus always cheaper?
No. For small monthly volume, the monthly fees associated with interchange-plus can outweigh the savings. It tends to be cheaper at higher volume or larger tickets.
Why do some providers push tiered pricing?
Because the provider controls which transactions fall into expensive tiers, it can earn more margin without a transparent line item. That does not mean every tiered plan is bad, but you should ask for tier definitions in writing.
Can I switch from flat rate to interchange-plus later?
Usually yes. If you use a gateway that supports multiple processors, switching may not require rebuilding checkout. Check your current contract for termination terms.
Sources
- Federal Reserve Board — Regulation II and debit card interchange
- Federal Trade Commission — business guidance about contracts and advertising claims
- Consumer Financial Protection Bureau — general financial education resources
