Your MCC, set once and charged against forever.
A four-digit code describing what your business does determines which published interchange tables you are priced against. It is assigned at boarding, rarely reviewed, and occasionally wrong in a way that costs money every month.
What this page settles.
Three questions, in the order most people ask them.
What the code does
A merchant category code is four digits describing what your business sells. Restaurants have one, grocery stores have another, charities, fuel stations, professional services and several hundred other categories each have their own.
It is assigned by your acquirer when you are boarded, from what the application said about your business.
Its importance is simple: the card networks publish different interchange rates by merchant category. A supermarket is priced against supermarket tables. A charity is priced against charity tables, which are deliberately favourable. A restaurant is priced against restaurant tables.
So your MCC does not adjust your rate at the margin. It decides which set of published rates you are being priced against at all, on every transaction, permanently, until somebody changes it.
Why a wrong one costs money
Because the tables genuinely differ, and nothing about your statement will tell you that you are on the wrong one.
A business coded as general retail but genuinely operating as, say, a grocery or a charity is being priced against a table that was never meant for it. The cost shows up as an effective rate that is slightly higher than it should be, on every transaction, forever. It does not look like an error because it does not produce an error. It just produces a number.
The amounts involved are usually modest per transaction and substantial over years, which is exactly the profile of a thing nobody checks.
It is also worth saying the inverse: sometimes a wrong code is cheaper than the right one. That is not a windfall, it is an inaccuracy in your merchant record, and it is the kind of thing that surfaces awkwardly during a risk review.
How codes get assigned wrongly
Rarely through anybody’s bad faith. Usually through one of these:
The application was vague. “Retail” covers a lot of ground, and whoever keyed it picked the nearest general code.
The business changed. You started as one thing and became another. A café that became a restaurant, a retailer that moved mostly online, a shop that added a kitchen. The code did not follow.
You genuinely span two categories. A hardware shop with a hire department, a bakery with a sit-down area. One code has to be chosen and the choice has consequences.
Nobody asked. The code was filled in by a salesperson in a hurry, from a dropdown, in a meeting that was mostly about rates.
The pattern that should prompt a check: your business today is noticeably different from the business described on the paperwork you signed.
Finding yours and checking it
Find it. Ask your processor, or look at your merchant agreement, welcome pack or statement. Four digits.
Look it up. The card networks and several industry bodies publish MCC lists. Find the description attached to your code.
Read it honestly. Does that description match what you actually sell, today, for most of your revenue? Not what you intended to sell, and not what you sold three years ago.
If it does not, that is worth a phone call. Not because there is necessarily money in it, but because an inaccurate merchant record is worth correcting on its own terms.
Do this once. It is a fifteen-minute job that most merchants never do, and it sits alongside the other five things that genuinely move interchange — all of which are configuration rather than negotiation.
Getting it changed
It is a request to your acquirer, supported by evidence of what your business actually does — a website, a menu, a description of your revenue split.
Three things to expect:
It is not instant. There is an underwriting element, because the code also affects how your risk is assessed.
A genuinely mixed business may not get the code it wants. If half your revenue is one thing and half another, the acquirer picks one, and their reasoning is about risk as well as category.
Do not push for a code because it is cheaper. A code has to describe what you do. Pressing for one that does not is misrepresentation in your merchant record, and the downside — a risk review, a held payout, a terminated account — is far larger than the interchange difference it was meant to capture.
If your current provider will not engage with a well-evidenced correction, that is worth noting. It is a reasonable request and a short conversation at an acquirer that is paying attention.
What we charge
Interchange + 0.50% + 10¢ in person, interchange + 0.75% + 25¢ keyed, interchange passed through at cost — which means the tables your MCC selects are the tables you actually pay, visibly, rather than an input into a bucket you cannot see.
Tell us what you sell and send a statement. We will tell you what code you are on and whether it matches the business you described to us.
While we are on the subject
Where do I find my MCC?
Ask your processor, or look at your merchant agreement or welcome documentation. Some statements print it. It is a four-digit number.
Can I choose my own MCC?
No. It is assigned by your acquirer based on what your business does, and it has to reflect reality. Choosing a code because it has cheaper interchange is misrepresentation, not optimization.
Does a wrong MCC always cost more?
Not always, and occasionally a wrong code is cheaper, which is its own problem because it is still inaccurate. The point is accuracy, with cost as the usual consequence of getting it wrong.
How hard is it to change?
It is a request to your acquirer with evidence of what you actually do. Straightforward when the case is clear, slower when your business genuinely spans two categories.