Start with the principal you have not yet paid
A gym, long-term course or recurring service may stop operating while its credit-card installments continue to be billed.
A refund claim against the business and a defense against paying the credit provider require separate review.
This calculator organizes unpaid principal and the requirements for reviewing a defense request for one personal credit-card installment contract in Korea.
Who is this for?
It supports consumers affected by closure or non-supply, including family members helping organize a parent or spouse's card records.
Rather than treating the original price as a full refund, it reconciles the actual agreement, unpaid ledger and evidence for submission.
It uses Korean rules for 2026; the result is not legal advice, issuer approval, discharge of debt or a guaranteed refund.
Check 200,000 KRW, 3 payments and 2 months separately
The familiar description of a 200,000 KRW, three-month installment purchase compresses several distinct requirements.
The Act specifies price, payment count and span separately, so check each against the agreement.
Credit-card installment price, count and payment-span thresholds| Requirement | Threshold | Record to verify |
|---|
| Credit-card installment price | At least 200,000 KRW | Confirmed price of one contract |
| Split payments | At least 3 | Agreed total payment count |
| Payment span | At least 2 months | First to last agreed payment date |
Article 2(1)(b) also requires supply to have been agreed before payment in full.
Actual non-supply and the original agreement to supply before full payment are different questions.
The general non-card indirect-installment threshold of 100,000 KRW is not used for a credit-card transaction.
For a first payment on 2026-08-15, the two-calendar-month boundary is 2026-10-15.
A last date of 2026-10-14 is one day short; 2026-10-15 meets the boundary.
2026-01-31 maps to 2026-03-31, and 2026-12-31 maps to 2027-02-28; this is not a fixed 60-day calculation.
Understand installment price, principal and snapshot
Contract installment price
This is the price basis of one contract used for the threshold.
If principal and fees are combined, verify the correct basis with the contract and issuer.
Do not substitute the unpaid balance or aggregate separate card purchases.
Principal excluding fees
This is the total principal scheduled for the same card transaction.
The sum of scheduled row amounts must equal it, and it cannot exceed the contract installment price.
Including fees or interest in paid principal would incorrectly reduce the remaining principal.
Ledger snapshot date
Reconcile principal actually paid through this date against statements and payment records.
A snapshot before notice cannot describe the balance at the later exercise, so verify the dates.
Include billed but unpaid principal as well as installments that have not yet been billed.
Ground and confirmations
Select the ground using records of closure, termination or non-supply.
If contract, ground, ledger or issuer notice remains unverified, the arithmetic balance stays visible while eligibility is pending.
Your confirmation is not issuer acceptance or a court finding.
Unpaid-principal formula and installment ledger
Paid principal = Σ paid principal in each row
Remaining principal = Σ(scheduled principal − paid principal)
Total principal = paid principal + remaining principal
Enter the amount actually paid even if a row is only partially paid.
A 100,000 KRW installment with 40,000 KRW paid has 60,000 KRW remaining.
The calculation sums rows rather than inferring payment from a count, so it supports unequal and partial payments.
The equal-ledger helper creates provisional editable rows.
It assigns floor(principal ÷ count) to each row and adds 1 KRW to the early rows for the remainder, preserving the total.
For 200,000 KRW over 3 installments, the rows are 66,667, 66,667 and 66,666 KRW.
This does not claim that an issuer uses that allocation; edit the rows to match the actual statement.
Rebuilding with a fully paid count replaces existing rows and clears ledger confirmation.
Reconcile each row again when the real schedule is unequal or fees are billed separately.
Blank amounts, overpayment, a mismatched principal sum or a mismatched row count remove results and show input errors.
How to use the calculator
- Choose one contract.
Verify personal consumer purpose, an original credit-card installment arrangement and the goods or service; prepare the contract and card receipt.
- Enter the full agreement.
Separate installment price from principal, then enter total count, first and last payment dates and agreed supply before full payment.
- Reconcile the snapshot ledger.
Enter scheduled and actually paid principal for every row, and compare the unpaid total with the issuer statement.
- Verify the ground and notice.
Check termination, non-supply or non-performance evidence, issuer notice and the dispatch or delivery date.
- Read status and unresolved checks.
Distinguish failed requirements, statutory exclusions, unsupported scope and pending review; collect any missing evidence.
- Prepare the submission.
Save a TXT review or print the ledger, snapshot, ground and confirmations together. Ask the issuer how to submit and handle the disputed payment.
Fictional worked examples
Four of twelve installments fully paid
Assume 1,200,000 KRW of principal with no fees, divided into 12 payments of 100,000 KRW, with 4 fully paid.
Paid principal is 400,000 KRW; remaining principal is 800,000 KRW across 8 unpaid installments.
If personal original credit-card installments, the payment span, statutory ground, notice and ledger are all confirmed, the principal review amount is 800,000 KRW.
With missing confirmation, the same arithmetic 800,000 KRW remains visible but the request-review amount is pending.
A 200,000 KRW contract with 10,000 KRW unpaid
For installment price and principal of 200,000 KRW, use scheduled rows of 66,667, 66,667 and 66,666 KRW and paid rows of 66,667, 66,667 and 56,666 KRW.
Paid principal is 190,000 KRW, remaining principal is 10,000 KRW, and one row is partially paid.
The 200,000 KRW threshold applies to contract price and is not applied again to the 10,000 KRW balance.
All principal already paid
If all principal is paid, unpaid principal available for a new refusal review is 0 KRW.
That does not resolve the underlying non-supply dispute; a refund of paid amounts or damages requires separate review.
Do not read this result as a refund of 0 KRW.
The six grounds in Article 16(1)
- Contract not formed or void: verify formation and the basis of invalidity; dissatisfaction with the contract is different.
- Cancellation, rescission or termination: verify an effective end to the contract, the notice and its legal basis.
- All or part not supplied by the agreed time: preserve the agreed supply time and actual delivery or service records.
- Warranty obligation not performed: record the defect, responsibility and requests for performance.
- Non-performance prevents the contract purpose: verify the actual effect of closure or stopped services on the contract.
- Lawful withdrawal under another law: verify that law's requirements and effective exercise; no generic withdrawal period is automatically applied.
Not using a service for personal reasons alone does not establish a statutory ground.
Where grounds overlap, select the main ground and preserve all supporting records.
A termination notice is not necessarily effective in every case; leave confirmation pending if its effect is disputed.
Separate issuer notice from the supporting documents
Article 16(2) requires notice of refusal to the credit provider before refusing payment.
A refund request sent only to the business is different from refusal notice to the issuer for the transaction.
Keep written content, dispatch evidence such as certified mail, and issuer receipt records so dates and recipients can be reconciled.
Dispatch, receipt and ledger snapshot are different dates
Written exercise takes effect on dispatch.
Article 16(5) requires written non-acceptance within 5 business days for the seller or 7 business days for the credit provider after receipt if the ground is not statutory. Article 16(6) provides deemed acceptance when the required notice is not given.
These depend on holidays, actual receipt, grounds and response content, so the calculator does not determine a deadline or deemed acceptance.
Article 16(7) protection against adverse treatment also requires review of lawful exercise and the actual dispute.
- Contract, card receipt, installment price, schedule and actual payment records
- Supply time, service-use and non-supply records, closure or unperformed-warranty evidence
- Termination or withdrawal records, transaction-specific refusal notice and dispatch / delivery / receipt evidence
- Review showing the snapshot, unconfirmed requirements and unpaid principal by row
The legal range is the installments actually unpaid when refusal is exercised.
The calculator does not backdate a current ledger to an earlier notice; obtain a contemporaneous statement if needed.
Scope and interpretation limits
Statutory exclusion and unsupported scope differ
Decree Article 4 excludes non-manufactured agricultural, fishery, livestock, forest and mineral products, medicines, insurance, securities / bills and real estate.
Act Article 3 excludes commercial-purpose business transactions but has an exception for a business buyer on the same position and terms as a consumer. That exception is routed to separate review.
Motor vehicles, later payment conversion, direct installments and prepaid contracts are only outside this tool's narrow scope.
A valid arithmetic balance with missing ground, contract or notice confirmation is an eligibility review pending.
Ready to review a defense request means that entries and confirmations support a request candidate; it does not mean automated filing or completed legal adjudication.
Actual payment, contractual performance and issuer-recognized amounts must still be checked against original records and the case process.
The 1-billion-KRW and 120-installment limits are calculator limits, not statutory caps.
Only principal is calculated; fees, interest, separate penalties and refunds of paid amounts are not added.
Do not stop the entire card bill on your own; confirm disputed-transaction submission and payment handling with the issuer while keeping normal transactions separate.
Frequently asked questions
Does an installment price of exactly 200,000 KRW qualify?
The credit-card price test is inclusive: an installment price of 200,000 KRW meets it, while 199,999 KRW does not.
Price alone does not establish a defense.
Payment count, span, agreed supply before full payment, a statutory ground and notice must also be reviewed.
Why do people say three months when the Act says two months?
Article 2(1)(b) requires at least 3 payments spread over at least 2 months.
Three monthly payments normally span two months from the first payment to the last.
The calculator checks the actual agreed count and first-to-last payment dates independently, rather than an advertising label or service-use period.
Must the unpaid balance also be at least 200,000 KRW?
The threshold applies to the installment price of the same contract, not the balance.
A 200,000 KRW contract with 190,000 KRW of principal already paid still meets the price test with only 10,000 KRW remaining.
Reconcile the amount unpaid at the exercise of refusal; previously paid amounts are separate.
Can this recover installments already paid?
Article 16(3) limits the refusal against the credit provider to the installments still unpaid when refusal is exercised.
This tool does not calculate a refund of paid amounts.
Contract termination, consumer mediation or another remedy may be needed to examine refunds or damages separately.
Can I stop paying when I hear the business has closed?
Closure can support evidence of non-supply or failure of the contract purpose, but a rumor or concern alone is insufficient.
Verify the agreed supply time, actual performance and termination, then notify the issuer of refusal for this transaction.
Confirm payment handling during the dispute and keep other normal transactions separate.
What about later payment conversion or a motor vehicle?
Lump-sum purchases later converted to installments, direct installments, prepaid arrangements and motor vehicles are outside this calculator scope.
That does not mean every legal right is absent.
Motor vehicles are not in Decree Article 4, so review withdrawal limits, issuer terms and the defense separately for the actual case.
Do I enter dispatch or receipt of a written notice?
Written exercise takes effect on dispatch under Article 16(4), so enter the dispatch date.
For non-written notice, use the date it reached the issuer only if the content and date are evidenced.
The seller 5-business-day and credit-provider 7-business-day non-acceptance rules run from written receipt.
This tool does not calculate deadlines or deemed acceptance.
How do I enter partial payments, fees and multiple purchases?
Enter actual paid principal for each installment, including partial payments.
Separate the contract installment price from principal excluding fees and interest.
Record only principal for this transaction; do not combine separate contracts or an entire card bill to reach the threshold.
Confirm any refusal of fees or interest and billing adjustments with the issuer.
Official sources and effective dates
The official National Law Information OPEN API was checked on 2026-10-08 using the current effective-date text.
The Installment Transactions Act uses MST 289407, Act No. 21906, effective 2026-09-08, Articles 2, 3, 6 and 16.
The Enforcement Decree uses MST 287001, Presidential Decree No. 36416, effective 2026-07-01, Articles 4 and 11.
This is distinguished from the scheduled 2027-09-09 text that the promulgation-date API may return. Entering a future date does not automatically apply scheduled rules.
Recheck requirements, amounts, dates and guides if these articles change.
The rule effective date is distinct from the actual contract date, terms, agreed supply time, non-performance, notice and payment ledger; reconcile each with original records.
Reconcile the unpaid ledger, then prepare the next action
Gather the contract and card statements and enter your actual figures above.
Update unresolved checks after verifying records, then submit the TXT review with supporting documents to the issuer.
Review consumer mediation separately if a refund of paid amounts or a compensation dispute with the business remains.