Compare internet cancellation repayments with switching rewards
A joining reward can look attractive while an existing internet contract still has months left to run.
Comparing that reward with one cancellation figure can miss IPTV repayments, equipment costs, installation fees and discounts lost on family mobile bills.
This calculator brings those amounts together and compares switching now, waiting for all relevant contracts to expire and renewing with the current carrier.
Every alternative ends on the same date, so a three-year period starting today is not compared with a different three-year period starting much later.
Korea-based 2026 contract planning
The automatic formulas reference Korean carrier terms, with all amounts in KRW.
They do not apply a universal cancellation percentage or determine whether an offer or exemption is legally available.
Use itemized carrier quotes and like-for-like new and renewal offers to decide which dates need closer review.
Confirm installation availability, actual cancellation and reward conditions before making the final choice.
Inputs and the scope of each amount
Separate service contracts
Enter the carrier, internet application date, service start, confirmed expiry and proposed cancellation date separately.
IPTV added later can expire on a different date, as can a mobile contract moved at the same time.
If mobile service stays active, do not include a mobile cancellation repayment or remaining device installment principal.
Enter only the mobile bundle discount that will actually disappear.
Quote versus cumulative discount
Quote mode uses the repayment reported by the carrier for the proposed cancellation date.
Reform mode instead needs the cumulative contract discounts received through that date, which are not the cancellation fee itself.
Distinguish monthly discounts from their actual billed cumulative amount.
A blank quote is unknown; an entered zero means confirmed zero or an excluded item.
One-time and monthly costs
Include new installation, equipment return or damage costs and any overlap between old and new service.
Compare the same speed, channel scope, equipment rental and VAT treatment in both monthly bills.
Lost family mobile discounts are a separate monthly cost.
Do not add a discount loss already reflected in either internet bill.
Rewards and renewal offers
Enter the new cash reward, usable voucher value, required retention period and expected use of the new service.
Any clawback of the old joining reward is a separate repayment, with its own confirmed end date.
Other equipment or bundle repayments also need their own confirmed zero-repayment date.
Enter the renewal monthly fee and reward from a written offer; leave its monthly fee blank when unknown.
Missing quotes allow partial results but prevent an overall lowest-cost decision.
The 2023 internet discount repayment reform
Automatic reform estimates cover ordinary new one-, two- and three-year internet contracts within the verified application-date rules.
Use quotes for renewals, bulk or special plans, four- or five-year terms, suspended service, price changes and exemption cases.
The underlying statutory framework does not itself supply one nationwide repayment formula.
Cumulative discounts and remaining days
At or before threshold: repayment = cumulative contract discounts
After threshold: repayment = cumulative discounts × remaining contract days / (total contract days − threshold)
On or after confirmed expiry: that contract repayment = KRW 0
Used and total days are calendar-day differences between the entered dates.
Enter the first date on which the carrier confirms no repayment, rather than assuming its displayed expiry always has that meaning.
A three-year date range is not always 1,095 days because of leap years.
Korean carrier reform dates and repayment thresholds for one-, two- and three-year internet contracts| Carrier | Application date from | 1 year | 2 years | 3 years |
|---|
| KT | 2023-09-08 | 180 days | 180 days | 180 days |
| SKB / SKT | 2023-09-27 | 90 days | 180 days | 240 days |
| LG U+ | 2023-11-01 | 90 days | 180 days | 240 days |
Using 180 days for every three-year contract can understate SK Broadband and LG U+ repayments.
Confirm that the relevant terms actually apply to the individual contract.
Future cumulative discounts add the entered monthly discount to the actual cumulative amount through the proposed cancellation date.
Partial future months use the actual day fraction of calendar months anchored to that date; this is a budgeting assumption, not a reproduction of carrier billing rules.
KT legacy internet and IPTV repayment bands
Verified bands are available for KT internet applications from 2016-04-01 through 2023-09-07 and ordinary KT IPTV contract-period discounts from 2016-04-01.
The estimate assumes the entered monthly discount stayed constant throughout the contract.
Each historical band contributes its own discount amount multiplied by one minus that band’s penalty discount rate.
Do not apply the last band’s rate to the entire cumulative discount.
Use quotes for changed prices, renewal reductions, differently governed rental or bundle items, and other carriers’ IPTV contracts.
One- and two-year rates
The one-year bands are months 1–6 at 0%, 7–9 at 20% and 10–12 at 130%.
The two-year bands are months 1–6 at 0%, 7–12 at 60%, 13–16 at 95%, 17–20 at 140% and 21–24 at 180%.
These are penalty discount rates; the repayment contribution uses one minus the rate.
Rates above 100%
Later bands of 110%, 125%, 170% and 280% make negative contributions that reduce cumulative repayment.
Clamping each negative contribution to zero would remove this reduction.
Only the final sum has a zero floor, and the confirmed contract expiry sets that repayment to zero.
KT three-year ordinary contract penalty discount bands| Usage band | Penalty discount rate |
|---|
| Months 1–6 | 0% |
| Months 7–12 | 30% |
| Months 13–16 | 65% |
| Months 17–20 | 75% |
| Months 21–24 | 100% |
| Months 25–28 | 110% |
| Months 29–32 | 125% |
| Months 33–34 | 170% |
| Months 35–36 | 280% |
A constant KRW 1,000 monthly discount on a three-year contract produces KRW 6,000 + 4,200 = 10,200 after 12 months.
Adding later bands produces KRW 12,600 after 24 months and zero at the 36-month expiry.
A partial final month uses the actual day fraction of the service-start calendar month, so use quotes when billed discounts have changed.
Step-by-step use and carrier questions
- Collect start dates and the first zero-repayment dates for internet, IPTV and any mobile contract being moved.
Ask for separate internet, TV, equipment-rental, bundle and old-reward clawback amounts to identify overlapping totals.
- Choose carrier quote mode or the automatic formula actually covered by the contract.
Do not borrow another carrier’s IPTV bands when the applicable terms have not been verified.
- Enter like-for-like new monthly bills, cash and usable vouchers, installation costs and lost family discounts.
Ask whether the quoted monthly fee continues after the new contract expires.
- Add a renewal offer and a common comparison horizon.
If the overall decision is pending, obtain missing quotes or change the horizon and calculate again.
- Save the input assumptions and results as TXT or print the review.
Keep it with the dated offers; it is not a cancellation application or activation confirmation.
Worked example: what remains of a KRW 400,000 reward?
This is an illustrative calculation, not a live offer or average cancellation fee.
Assume an ordinary KT internet contract runs from 2025-01-10 to 2028-01-10, with cancellation on 2026-10-10.
Usage is 638 days out of 1,095 days, and actual cumulative discounts through cancellation are KRW 231,000.
Repayment and 15-month benefit
231,000 × (1,095 − 638) / (1,095 − 180) = KRW 115,374
400,000 − 115,374 − 36,000 − (5,000 × 15) = KRW 173,626
Both current and new monthly internet bills are KRW 33,000, the cash reward is KRW 400,000, installation costs KRW 36,000 and lost family discounts KRW 5,000 per month.
The 15-month baseline costs KRW 495,000; switching costs KRW 321,374, giving a net benefit of KRW 173,626.
The upfront gain of KRW 248,626 shrinks by KRW 5,000 every month, so a large initial reward does not imply an advantage for every longer period.
The common comparison ends on 2028-01-10, exactly at internet expiry.
Switching on that endpoint is outside this period, so the waiting alternative receives neither a joining reward nor installation cost within it.
This avoids mixing benefits from different future periods.
Add a separate IPTV repayment if IPTV is also being cancelled.
Read the curve, break-even dates and renewal comparison
Why future amounts are unknown
A carrier quote applies to the specified cancellation date.
Without evidence for a later early-cancellation amount, quote mode leaves that amount unknown until the confirmed expiry.
Curve gaps are not zero, and the chart does not connect across unknown dates.
Two different break-even questions
The first date when repayments fit inside the reward differs from the first date with nonnegative benefit after installation, monthly bills and lost discounts.
The calculator samples monthly dates and actual expiry dates and identifies the first known qualifying candidate.
Unknown earlier dates prevent a definitive earliest-date claim; even a complete sample is not a daily optimum.
Upfront recovery months describe covering an initial loss with positive fixed monthly savings; zero or negative savings cannot provide that recovery.
Waiting and renewal use the same endpoint
The waiting date is the latest active contract expiry, other-repayment end date or old-reward clawback end date.
Before switching, the current fee applies; afterward, the new fee and lost family discount apply.
A transition inside a month splits that same month using its actual day counts.
Renewal uses the current fee until the same waiting date, then the entered renewal fee and a single renewal reward.
Events at or beyond the comparison endpoint are outside the period and receive no reward or one-time charge within it.
Use cases: moving home and reviewing family bundles
A fixed moving date
First confirm installation availability at the new address and the cost of transferring current service.
Compare the same scope, then change the proposed cancellation date to review alternatives.
Do not assume an installation or service-quality issue automatically grants an exemption.
Enter the quote after any carrier-confirmed reduction.
A parent’s family bundle
Collect lost discounts from each affected family mobile bill rather than examining only the internet bill.
Exclude mobile cancellation repayments when those mobile services stay active.
When internet and TV expire separately, review waiting until the last expiry.
Cancelling only part of the bundle requires a new itemized quote and separate assumptions.
Reward retention and calculation limits
- If expected service use is shorter than the entered reward-retention condition, both new cash and vouchers are entirely excluded in a conservative scenario.
This still does not include payment delays, condition-specific clawbacks or unknown early repayments on the new contract.
- Future switching rewards and installation costs are assumed identical to today’s offer; baseline, new and renewal monthly fees stay fixed.
Repeated switching or another reward after the new contract expires is not modeled.
- Each existing contract repayment becomes zero on its confirmed expiry date.
Equipment non-return, damage costs and ordinary unpaid bills do not disappear merely because a contract expires.
- Displayed amounts round to whole KRW and may differ from carrier proration, truncation, reductions or suspension accounting.
Use quotes when the actual discount history changed.
- Results do not recommend a carrier or decide reward legality, exemption eligibility, disputes or joining approval.
Payment and billing dates can create an immediate cash requirement even when the overall comparison shows a gain.
Frequently asked questions
Does repayment always fall as fewer months remain?
Not necessarily, because cumulative discounts also increase.
Automatic formulas use both remaining days and accumulated discounts.
Quote mode does not invent future amounts.
Why do three-year KT and SK Broadband results differ?
The verified threshold is 180 days for KT and 240 days for SKB / SKT and LG U+.
Check the application date and the actual scope of the contract before selecting automatic mode.
Can the internet reform formula also calculate IPTV?
This calculator does not apply the internet reform to IPTV.
Use verified KT IPTV bands or an itemized quote from the relevant carrier.
Should I enter zero when I do not have a quote?
Leave an unknown amount blank.
Entering zero treats the item as excluded or confirmed zero and can make costs appear smaller.
Do family mobile discounts matter if only internet moves?
Yes, if moving internet removes discounts from those mobile bills.
Enter the lost monthly amount, but exclude mobile cancellation repayments when mobile service remains active.
Is waiting for expiry always better?
Removing repayments is only one part of the comparison.
Bills paid while waiting, forgone monthly savings and future offers also matter.
Compare all alternatives to the same endpoint.
Is reward retention the same as the new contract term?
They are separate inputs.
Completing reward retention can still leave an early-cancellation repayment on the new contract, which requires a separate quote.
Does saving the review submit cancellation?
No.
TXT and printing preserve inputs and results.
Confirm actual cancellation, equipment return, activation and reward payment through the carrier.
Official sources and 2026 verification
Official materials were checked on 2026-10-06.
Direct National Law Information OPEN API calls confirmed the current Telecommunications Business Act, Article 28, MST 285185, effective 2026-10-01, and the Internet Multimedia Broadcasting Business Act, Article 15, MST 286115, effective 2026-05-19.
These provisions establish the terms framework; the numerical repayment rules come from official carrier terms and product guidance.
The public KT IPTV document includes supplementary provisions effective 2026-06-01 and the ordinary contract-period bands used here.
Recheck reform application dates, repayment thresholds, IPTV bands, renewal and suspension exceptions, equipment rules and reward conditions each quarter and after terms changes.
If legacy descriptions differ from current product guidance, the applicable individual contract version and carrier cancellation quote take priority.
Check the net benefit before setting a switching date
Collect itemized cancellation figures and new and renewal offers, then compare costs to one common endpoint.
Confirm that an advantage remains after repayments, installation costs and lost family discounts before scheduling cancellation and activation.