Merchant discount rate: what it is and how to work it out

The merchant discount rate is the fee you pay to accept a card payment, usually expressed as a percentage of the sale. Visa describes it this way: merchants don't pay interchange themselves; they "negotiate and pay a 'merchant discount' to their financial institution that is typically calculated as a percentage per transaction" (Visa). That financial institution is your acquirer, the bank behind your merchant account, which you usually deal with through your processor.

The merchant discount rate, often shortened to MDR, matters for two reasons. It's the number you're really negotiating when you compare processors. And Visa and Mastercard use it to cap how much you can surcharge a credit card. The catch is that many statements don't print it, so you have to work it out yourself. This guide shows how.

What does the merchant discount rate include?

Everything you pay on a card sale, bundled into one rate. Mastercard calls interchange "one component of the Merchant Discount Rate (MDR) established by acquirers" (Mastercard). Visa's interchange schedule notes that the merchant discount can also cover the processing services your acquirer provides (Visa USA Interchange Reimbursement Fees).

In practice, it has three layers:

Interchange is the layer that moves the most, by card and by how the card was taken. Our guides to Visa interchange rates and Mastercard interchange rates list the current published figures.

Monthly flat fees, such as a statement fee, a PCI fee or a gateway fee, usually sit outside the per-sale rate. They don't change your merchant discount rate, but they do change what cards cost you overall. That's where the effective rate comes in.

How is the merchant discount rate different from your effective rate?

Your merchant discount rate is what a card sale costs you. Your effective rate is what card acceptance costs you overall: every fee on the statement, including the monthly ones, divided by your total card sales.

Three related numbers get mixed up all the time:

On a flat-rate plan, the merchant discount rate is simply your flat rate, plus any per-sale fee. On interchange-plus pricing, it changes with every sale, because interchange does. That's why Mastercard's surcharge rule talks about your "average effective merchant discount rate": it's the rate averaged across your Mastercard credit sales.

Canada makes this easier. The Code of Conduct for the Payment Card Industry in Canada requires your monthly statement to show your effective merchant discount rate for each card type (FCAC). In the US, you'll usually have to do the division yourself.

How do you calculate your merchant discount rate?

Divide the fees charged on a card type by the sales on that card type, for the same period. Step by step:

1. Pick a period. One month works; twelve months gives a steadier number.
2. Choose one card type, such as Visa credit.
3. Add up every fee charged on those sales: interchange, network fees, and your processor's percentage and per-sale fees.
4. Divide by that card type's sales volume for the same period.
5. Repeat for each card type you accept.

Say a dental office in Salt Lake City takes $60,000 in card payments in a month. All figures are illustrative.

The Visa credit line breaks down like this: $510.00 in interchange, $30.00 in network fees, and a markup of 0.15% plus 10 cents a sale ($45.00 plus $30.00). That's $615.00 on $30,000, or 2.05%.

Now add the monthly fees. If the office pays $45.00 a month in statement, PCI and gateway fees, its total is $1,165.50, and its effective rate is $1,165.50 divided by $60,000, or about 1.94%.

So the same office has a 2.05% Visa credit rate, a 1.87% blended rate and a 1.94% effective rate. None of them is wrong. Each answers a different question, and mixing them up leads to bad decisions, especially on surcharges.

Watch the per-sale fee when you do this. A 10 cent fee is 0.50% of a $20 sale but only 0.05% of a $200 sale, so a cafe and a furniture store on identical pricing can end up with very different merchant discount rates.

Why does the merchant discount rate matter for surcharging?

Because both big networks tie their US surcharge caps to it. Visa lets you surcharge credit cards up to your merchant discount rate for the card being surcharged or 3%, whichever is lower, and requires 30 days' notice to your acquirer before you start (Visa). Mastercard caps a surcharge at the lesser of your average effective merchant discount rate or 4% (Mastercard). Neither network allows surcharges on debit or prepaid cards.

So 3% and 4% are ceilings, not targets. For the dental office above:

If the office wants one surcharge rate for every credit card, it has to fit under both caps, so 2.05% is its limit. Charging a flat 3% would collect 0.95 points more than Visa allows on Visa credit, about $285 a month on $30,000 of Visa credit sales.

Notice that the blended rate is the wrong number here. At 1.87%, it's dragged down by cheap debit sales that can't be surcharged at all. Visa's cap is tied to the credit card being surcharged, so use the card-type rate.

State law can be stricter than the networks. Colorado, for example, caps surcharges at either 2% of the purchase or the merchant discount fee you pay (Colorado General Assembly); our Colorado page has the details. Our guide to credit card surcharging rules by state covers the rest, and our surcharging program handles compliance, disclosure and setup. American Express has its own rule built on equal treatment rather than a percentage cap, which our guide to American Express merchant fees explains.

Canada uses the same idea. Visa Canada says a Canadian merchant "may only assess a surcharge that does not exceed the merchant discount rate," with an absolute maximum of 2.4% (Visa Canada). Quebec doesn't allow fees for paying by debit or credit card at all (Office de la protection du consommateur); see our Canada page and our guide to credit card surcharges in Canada.

What is a good merchant discount rate?

There isn't a single good number, because much of the rate is interchange, and interchange depends on cards you don't choose. Two businesses on identical pricing can have very different merchant discount rates.

Here's an example using Visa's April 18, 2026 interchange rates and the same made-up markup of 0.20% plus 10 cents, on a $40 sale:

The processor charged both sales the same markup. The rewards card online simply costs more to accept. So when you compare your rate with a friend's, or with a number you read somewhere, you're mostly comparing card mixes.

The better test is the markup, the only layer you can negotiate. On interchange-plus pricing, it's printed on your statement. On a flat rate, you can estimate it by subtracting interchange and network fees from what you paid, but only if your processor will show you those costs. Our comparison of interchange-plus and flat-rate pricing explains why that visibility matters.

How can you lower your merchant discount rate?

Lower the markup, and make more of your sales qualify for cheaper interchange.

• Get quotes as interchange plus a markup, so you're comparing the part that differs.
• Dip or tap cards instead of keying them. Keyed sales usually land in pricier interchange categories.
• Close your batch daily. Mastercard's rate requirements include how much time passes between authorization and clearing.
• Check your merchant category code. Category-based rates depend on it.
• Send line-item data on commercial card sales if you sell to other businesses.
• Watch per-sale fees if your tickets are small, because they weigh more on a $10 sale than a $100 one.

And when it isn't worth chasing: if your processor's markup is already small and your card mix is mostly premium rewards cards, your merchant discount rate will stay high no matter who processes for you. At that point, a lower rate means changing how customers pay (a cash or debit incentive, or a compliant surcharge), not switching processors.

What should you ask your processor about your rate?

Ask for the answers in writing, before you sign or the next time you review your account:

1. What's my merchant discount rate on Visa credit and on Mastercard credit for the last 12 months? If you plan to surcharge, you need these two numbers.
2. Is interchange passed through at cost, or is it folded into my rate?
3. What's your markup, as a percentage and a per-sale fee, and can it change during my agreement?
4. Which fees sit outside the rate, such as monthly, PCI, gateway or batch fees?
5. Do network fees appear as their own lines, or are they inside the rate?
6. How much notice do I get before any of this changes?

A processor that can't answer the first question quickly probably can't tell you whether your surcharge is within the networks' caps either. On our interchange-plus pricing, each layer shows on the statement, so the math in this guide takes minutes.

Common mistakes with the merchant discount rate

• Comparing a quoted rate with an effective rate. A 2.0% quote and a 2.4% effective rate on your current statement aren't measuring the same thing.
• Using your blended rate as your surcharge cap. Visa ties its cap to the credit card being surcharged.
• Forgetting the per-sale fee. It turns a low headline percentage into a high rate on small tickets.
• Assuming a flat rate is your whole cost. Monthly fees still apply on top.
• Treating 3% as a benchmark. It's Visa's ceiling for surcharges, not a measure of what your rate should be.

The next step

Take last month's statement and work out your merchant discount rate for Visa credit and for Mastercard credit, then your effective rate overall. If the statement doesn't give you enough detail to do that, that's worth knowing too. Send it to us for a free statement review and we'll calculate each rate for you and show which part is negotiable. Our page on credit card processing fees explains the layers in more detail.