Card Terminal Fixed Cost Calculation: 7 Common Mistakes That Cost You Money — From Duplicate Billing of Rent, Management Fees, and Communication Charges to Long-Term Contract Traps
Why Is Card Terminal Fixed Cost Calculation So Complicated? If you feel like fixed costs are higher than your monthly settlement, there's a high chanc...
Why Is Card Terminal Fixed Cost Calculation So Complicated?
If you feel like fixed costs are higher than your monthly settlement, there's a high chance you haven't clearly identified how much you're paying to which companies for rent, monthly management fees, and communication charges. This article is based on Shim Jae-woo, CEO of TheKL Link, drawing from 5 years of experience consulting on thousands of card terminal contracts. It outlines 7 fixed cost traps that small business owners commonly miss, with concrete examples. The general principles and monthly cost structure were covered in Part 1's comprehensive guide, so this article focuses on "warnings about mistakes you must avoid in your actual business location."
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When Rent and Monthly Management Fees Are Being Charged Simultaneously Without Knowing It
If the concept of card terminal rental isn't clear, you can end up paying duplicate costs for the same service. In the actual case of A convenience store owner, they thought they were paying "monthly rent of 30,000 won" to PG company A, but upon closer inspection of the settlement statement, they discovered a separate "monthly management fee of 20,000 won" was accumulating, resulting in 50,000 won in monthly expenses. They didn't even know what the difference was between these two items.
Real case: B ramen restaurant (located in Jung-gu, Seoul) paid a combined monthly rent and management fee of 600,000 won for 3 years, but when replacing the terminal, they failed to read the condition that "rent is discontinued and only management fees are maintained," so after adopting the new terminal, only a 180,000 won monthly management fee remained. There was no ultimate loss, but if you don't know the difference between rent and management fees before signing, you can fall into a bigger trap.
What NOT to do: ❌ Only knowing "monthly cost is X amount" without reviewing itemized details | ❌ Failing to confirm auto-renewal management fee conditions after rent expires | ✓ Note all fee items in the settlement statement (rent, management, communication, added services) → Ask the PG company before signing, "Are all these items really necessary?"
Key point: Rental fees and monthly management fees are separate line items that must be specified in the standard contract. If not specified, they are hidden costs.
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When Communication Fees Are Being Charged Simultaneously by PG Company, Telecom Provider, and Terminal Manufacturer
Card terminals require LTE or WIFI communication for credit card transactions. However, if you don't track where communication fees are going, you can end up paying three times over.
Real case: C café (located in Gangnam) owner was charged "communication fee of 8,000 won per month" on the PG company settlement statement, separately "IoT device management fee of 3,000 won per month" on the KT internet bill, and "device maintenance fee of 5,000 won per month" through the terminal manufacturer's direct app. A total of 16,000 won monthly, but most of the PG company charge was unnecessary (KT broadband was already sufficient).
Warning signs: If your settlement statement shows multiple items like "communication fee/device maintenance fee/IoT charges," there's a 70%+ chance of duplication. Especially if your online payment system is built on cloud services from telecom providers like SKT, KT, or LG, additional PG communication fees are unnecessary.
What NOT to do: ❌ Simply paying the "communication fee" item on the settlement statement | ❌ Failing to verify "included in basic fee" explanations | ✓ List all items from the past 3 months of settlement statements in Excel → Check if there are duplicate-named items → Email the PG company's technical team asking, "Is this communication fee necessary?"
Key point: Communication fees should only be charged by one PG company. If there are 2 or more, request immediate removal.
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When You Signed Long-Term Contracts with Auto-Renewal Conditions Without Reading Them
Card terminal contracts often contain "auto-renewal" clauses, and there's a trap where fees increase significantly at renewal time. It's common for rental or monthly management fees to more than double, separate from PG payment processing fees.
Real case: D convenience store owner signed under "2-year contract, monthly rent of 20,000 won," but missed the fine print in clause 16 of the contract: "Upon auto-renewal after 2 years, monthly rent becomes 45,000 won." They didn't realize this until they received the settlement statement exactly 2 years later, and in the 3rd year they eventually switched to another PG company (and paid another month's termination fee when switching).
Warning signs: If your contract contains "auto-renewal," "fee renegotiation upon renewal," "base rate increase clause," or similar language anywhere, highlight just that clause and ask your PG company representative in writing: "Exactly how much will it be at renewal?"
What NOT to do: ❌ Misunderstanding "auto-renewal" as simply "I can keep using it" | ❌ Signing the renewal document without comparing alternative providers starting 3 months before renewal | ✓ Start collecting competitor quotes 1.5 years after signing → Make final decision 2 months before renewal
Key point: 3 months before your 2-year contract ends, you must definitely renegotiate or terminate the contract.
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When "Optional" Added Services Recommended by Company Are Auto-Charged
When a PG company representative suggests during contract signing "How about adding payment data backup service (5,000 won per month) just in case?" most small business owners simply respond "Sure." But later, when checking the settlement statement, services recommended as optional continue to be charged unless you specifically request cancellation.
Real case: E restaurant owner was recommended "sales report by business partner (3,000 won per month)" as an added service during terminal setup and said "Yes, sure," but 6 months later had never actually seen that report. Only after carefully reviewing the settlement statement did they realize "Oh, this has been deducted this whole time" and immediately requested cancellation (billing stopped 2 months after cancellation request).
Warning signs: If items like "other added service charges," "information service fees," or "data fees" appear on your settlement statement in small amounts but accumulate continuously, it becomes a tens of thousands of won annual loss. Especially when building online payment systems, items like "cloud storage (10,000 won per month)" can be automatically added.
What NOT to do: ❌ Simply approving added services described as "optional" | ❌ Skipping over added service items on settlement statements as "just there" | ✓ At contract signing, have the representative specify in writing: "Never add any added services going forward" → If you discover new items on the settlement statement, file a dispute within 7 days
Key point: Every item on your settlement statement should only be those you explicitly requested. If you find unfamiliar items, request deletion immediately.
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When You've Contracted with Multiple PG Companies but Left Some Unresolved Without Proper Cancellation
As your business grows, you often sign contracts with multiple PG companies to separate online and offline payments, or for specific payment methods (delivery apps, prepayment, etc.). But if you don't formally cancel the existing contract, fixed costs continue to be charged.
Real case: F online mall (located in Jung-gu, Seoul) owner started with PG company A, then switched to B (offering discounted processing fees) as business expanded. However, thinking they had switched to B, they never formally requested cancellation from A, and A's "minimum transaction shortfall fee" (10,000 won monthly) continued being charged for 6 months. Later investigation showed that A had a clause stating "basic fees apply even without transactions."
Warning signs: "I thought I cancelled but it's still being charged" typically means either ① cancellation wasn't completed in writing or ② you missed cancellation conditions (e.g., minimum transaction requirements). This mistake is especially common when trying to replace offline card terminals after setting up online payment systems.
What NOT to do: ❌ Only informing the PG company representative verbally that "we won't use this going forward" | ❌ Thinking you've submitted cancellation documents without verifying contract status | ✓ Once your new PG company is confirmed, submit a "cancellation request form" to the old PG company → Verify one week later that you receive a "cancellation complete" email → Double-check the next settlement statement (about 1 month later) confirming that company's items are gone
Key point: For at least 2 months after switching PG companies, verify the old PG company's settlement statement items.
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When You Don't Know About "Projected Monthly Payment Amount" Conditions and Actual Transactions Fall Short
Many PG companies set an "expected monthly transaction amount" condition during contract signing. If this condition acts as a minimum guarantee (SLA), losses increase when transaction volume is low.
Real case: G café contracted based on "average monthly transaction amount of 10 million won, 200 transaction instances" with negotiated PG fees (1.8%). However, after COVID-19, average monthly transactions dropped to 3 million won, but due to the contract clause "processing fee surcharge (+1%) if performance falls short," they were actually paying 2.8% in fees. Without knowing, they paid approximately 2 million won in additional fees over 2 years.
Warning signs: If your contract contains "projected monthly transaction amount," "surcharge if transactions fall short," "minimum transaction shortfall fee," etc., then ① clearly interpret the standard and ② verify it matches your actual transaction trends every 6 months.
What NOT to do: ❌ Simply accepting the representative's statement "You'll probably do about 10 million won monthly, right?" | ❌ Ignoring contract terms even when actual transactions drop to half | ✓ Calculate average transaction amount for the past 3 months at least every 6 months → If there's a 30%+ difference from the projected amount, request contract adjustment from the PG company
Key point: You have the right to renegotiate your contract if transaction volume decreases.
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When You Mix Offline and Online Payment Systems and Aren't Aware of Double Fixed Costs
As business expands online, many companies set up both card terminals (offline) and separate online payment systems. However, if the fixed cost structures of the two systems are completely different, total costs can be far higher than expected.
Real case: H fashion mall used PG company A's card terminal at their offline store (monthly fixed cost 80,000 won, 2.5% PG fee). After opening an online mall, they contracted with PG company B (monthly fixed cost 120,000 won, 2.8% PG fee, separate cloud service fee of 50,000 won monthly), resulting in total monthly fixed costs of 250,000 won. If the two systems could have been integrated, they could have solved it for around 80,000 won monthly. One year's loss alone equals 200,000 won.
Warning signs: When getting card terminals and online payment systems from different companies, you absolutely must ask about "integrated package discounts." Especially in small business-dense areas like Jung-gu, Seoul, regional specialized PG companies (like TheKL Link) offer integrated solutions.
What NOT to do: ❌ Contracting offline and online payments separately (each generates minimum monthly fixed costs of 100,000 won+) | ❌ Failing to ask "Is there a discount if we integrate?" | ✓ Before switching online, definitely ask your current PG company, "I'm thinking of adding online transactions—what's the integrated fee?" → When quotes come in, compare with other companies' integrated rates
Key point: When possible, integrating online and offline payments with one PG company saves 30~50% in costs.
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3-Step Checklist for Accurately Calculating Fixed Costs at Your Actual Business Location
To avoid the 7 mistakes above, you must accurately calculate your fixed costs through the following 3 steps:
Step 1: Collect the past 3 months of settlement statements
Step 2: Categorize settlement statement items
Step 3: Inquire with PG company representative (in writing)
Core checklist by situation
| Risk Situation | Verification Method | Response |
| --- | --- | --- |
| Duplicate rent/management fee billing | Search settlement statement for similar items | Request PG company to explain difference between two items, then delete unnecessary one |
| Triple communication fee billing | Compare SKT/KT/LG statements + PG settlement statement | Confirm which is main telecom provider, then immediately cancel the other 2 |
| Auto-renewal trap | Read clauses 13-18 of contract | Start collecting competitor quotes 3 months before expiration |
| Hidden added services | Track "miscellaneous" and "service fee" items in statement | Cancel all items you didn't personally request |
| Unresolved PG company continued billing | Confirm unnecessary company names in past statements | Submit cancellation form, then confirm completion email after 1 week |
| Surcharge when transaction volume drops | Check "projected monthly transaction amount" clause in contract | Compare to past 3 months average, request renegotiation if 30%+ difference |
| Double fixed costs from online/offline mix | Add up monthly fixed costs of both systems | Consider integrated package with same PG company to reduce costs |
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Card Terminal Fixed Costs — Absolute DON'Ts — FAQ
Q1. I see "communication fee" on my settlement statement, but is it really necessary?
A: Mostly unnecessary. Card terminals only need LTE or WIFI communication to send transaction signals, but if your store already has KT or SKT internet, it's duplicate. Request immediately from your PG company to "remove communication fees." Cancellation typically takes 1-2 weeks.
Q2. I signed without noticing the "projected monthly transaction amount" condition—if my actual transactions are lower, what happens?
A: If your contract has a "processing fee surcharge if transaction performance falls short" clause, you'll incur losses. For example, if you negotiated 1.8% fees based on "1 million won monthly benchmark" but actually do 300,000 won monthly, rates can jump to 2.8%+ or higher. In this case, immediately negotiate with the PG company to "adjust the transaction amount standard." Especially for seasonal businesses, make sure to specify "renegotiation rights if transaction volume changes" during contract signing.
Q3. I was recommended added services (data backup, sales reports, etc.)—can I refuse?
A: You can absolutely refuse. In fact, specify in writing at contract signing: "Do not add any future added services." If unknown items later appear on your statement, you can file a "unauthorized charge dispute." Most added services are optional, and ROI is often poor.
Q4. I've contracted with multiple PG companies—how can I verify if I properly cancelled old contracts?
A: Check the settlement statement. If the old PG company statement continues showing items like "minimum transaction shortfall fee" or "base charge," the contract is still active. Request a "contract cancellation certificate" from the representative via email. Email records are preserved for future dispute evidence.
Q5. My card terminal rent is 30,000 won monthly—is that expensive?
A: It varies by business type and contract terms. For convenience stores, 20,000-30,000 won monthly is standard, but with high transaction volume, you can negotiate under 10,000 won. Also, upgrading from older terminals to latest models can reduce rent 50%. To check if your current contract is above market average, ask other business owners in your industry or PG consultants about "benchmark fees."
Q6. Do I absolutely need a separate payment system besides my card terminal to open an online shopping mall?
A: It depends on sales volume. If monthly transactions are under 5 million won, one card terminal alone is sufficient. But if monthly transactions exceed 10 million won, setting up a separate online payment gateway (PG company's cloud service) is more efficient. Always ask if the PG company offers an "integrated package." Separate systems increase fixed costs by 200,000+ won monthly, but integration can solve it for around 100,000 won.
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Conclusion: Monthly "Settlement Statement Item Check" Is Your Best Self-Defense
The most certain way to escape card terminal fixed cost traps is to develop a habit of comparing your settlement statement to the previous month the moment you receive it. If new items appear or existing items increased, ask why, and request immediate deletion if unnecessary. Especially before discussing PG payment fees, reducing fixed costs like rent, management fees, and communication charges will significantly improve net profit.