Some fees hide by being small. The monthly minimum hides by not being a fee at all — it is a threshold, and it only becomes a charge in the months you process the least, which for a seasonal business means exactly the months money is tightest. If your statement has ever shown a processing charge in a month you barely opened, a monthly minimum is the most likely explanation. Here is how the mechanism works, the worked math on the two account structures where it bites hardest, and the exact lines to look for.
What a monthly minimum actually is
A monthly minimum is the least amount of discount (processing) fees your processor expects to collect from you in a month. Processors earn a small percentage of every transaction — the discount rate — so an inactive account earns them nothing while still costing them servicing and compliance overhead. The minimum exists to cover costs on inactive or dormant accounts. The mechanics are simple: if your actual discount fees for the month reach the minimum, nothing extra is charged. If they fall short, you are charged the difference to reach it. Paying the full minimum in a month means you processed nothing at all. Canadian merchant guidance describes it the same way: the minimum is the least amount in discount fees the processor expects, and falling short triggers a top-up charge for the difference, even if few or no transactions occurred.
The catch: only some fees count toward it
The dangerous detail is not the threshold — it is the definition of what counts toward it, and the processor sets that definition. One provider may count all discount and per-transaction fees; another counts only its own discount/markup portion. On an interchange-plus plan this matters enormously, because interchange — the largest component of your processing cost — goes to the card networks and issuing banks, not to your processor, and typically does not count toward the minimum at all. Work the standard example: interchange plus 0.30% plus $0.10 per transaction, a $100 average ticket, average interchange of 1.9%. You pay about $2.30 per transaction in total — but only about $0.40 of it counts toward your monthly minimum. Against a $25 minimum, you need roughly 63 transactions — about $6,250 in monthly sales — just to clear a threshold that looks, on the rate sheet, like it should clear itself.
What the minimums run
| Source | Published range | Notes |
|---|---|---|
| Stripe's merchant-account fee guide | $20–$50/month | Charged as the difference if processing fees fall short |
| Merchant Maverick explainer | ~$25/month typical | Notes many of the best providers no longer use monthly minimums; still common in high-risk accounts |
| Small-business cost guides (2026) | $25–$50/month | Flag seasonal businesses as the hardest hit |
| LegalClarity merchant-account guide | ~$25 typical threshold | Emphasizes only the processor's markup counts, so several thousand in sales may be needed to clear it |
Note what is absent from that table: flat-rate processors. Square- and Stripe-style flat-rate pricing generally carries no monthly minimum, because the flat rate bundles the processor's margin into every transaction and there is no separate merchant account to keep alive. Monthly minimums are a traditional merchant-account feature — which is why they so often surprise merchants who switched from a flat-rate platform to a “cheaper” interchange-plus account without reading the fee schedule.
Who it bites: the two worked cases
The seasonal retailer. A garden or patio business processes heavily May through August and nearly nothing in January. On an account with a $25 minimum counting only markup: in January, with $400 in card sales generating roughly $2 in qualifying markup, the statement shows a $23 top-up — for a month the till barely opened. Across a four-month off-season, that is roughly $90–$100 a year paid for the privilege of being closed, on top of any statement or account fees that bill year-round.
The truly small account. A home-based service business processing $1,500 a month at the example rates above generates about $6 in qualifying markup — a $19 top-up every single month, or about $228 a year. That is frequently more than the entire savings the interchange-plus account promised over flat-rate pricing at that volume. Below a few thousand a month in card volume, the minimum can erase the rate advantage completely.
Larger businesses never see the charge, which is precisely why it survives: the merchants it affects are the ones least likely to read a full fee schedule, and the charge appears under labels — “monthly minimum,” “minimum discount,” “MDR minimum” — that do not announce themselves as a penalty for a quiet month.
Find it and fix it: the procedure
- Pull three statements: your busiest month, your quietest month, and last month. In the quiet month, look for a line labelled monthly minimum, minimum fee, or MDR minimum — and compare the processing-fee total against it.
- Ask the counting question in writing: “Which fees count toward my monthly minimum — discount only, or discount plus transaction fees?” The answer changes your break-even volume by an order of magnitude.
- Compute your qualifying volume. Take your average ticket and your markup per transaction; divide the minimum by the markup to get the transactions (and roughly the sales) you must process monthly to clear it.
- Negotiate from the number, not the feeling. Ask for the minimum to be removed, reduced, or waived for off-season months if you are seasonal — providers that still use minimums will sometimes waive them during downtime if asked upfront. Get any waiver in writing.
- Price the alternative honestly. If your volume cannot clear the minimum, compare the account's true annual cost (rates + minimum top-ups + statement/PCI/account fees) against a no-minimum flat-rate option at your actual volume — not at the volume the rate sheet imagines.
One contract warning: monthly minimums usually travel with the other traditional-account furniture — multi-year terms and early termination fees (commonly $200–$500 in published guides). If the minimum is what makes you want to leave, check the termination terms before you sign the exit paperwork, and time any switch to the contract's renewal window. The cheapest fix is always the one negotiated before signing: minimums are a standard, visible line in the fee schedule of any account that has one, and “no monthly minimum” is a reasonable thing to require in writing.
A note on Canadian statements
Canadian merchants will most often meet the monthly minimum on traditional accounts from the big domestic processors and their resellers, where the fee schedule is long and the minimum is one line among dozens. The label varies — monthly minimum, minimum discount fee, MDR minimum — and the counting rule is buried in the merchant agreement rather than the rate sheet, which is why the written question in step 2 of the procedure matters: the agreement, not the sales summary, governs what counts. If your statement is from a flat-rate platform, you will not find this charge at all, and a quiet-month processing line on such an account deserves a different explanation — check for statement, account or PCI line items first.
FAQ
Is a monthly minimum the same as a monthly account fee? No. An account or statement fee is charged every month regardless. A monthly minimum is a threshold: you pay only the shortfall, and only in months your qualifying fees fall below it. An account can carry both.
Do interchange fees count toward the minimum? Usually not — the processor decides what counts, and on interchange-plus plans typically only the processor's markup (the “plus”) counts. That is why the break-even volume is so much higher than merchants expect.
Can I get a monthly minimum removed? Often, yes — many providers have dropped them entirely, and they remain negotiable, including seasonal waivers. Ask before signing, or at renewal, and get the answer in writing.