The total value of the seonteagyakjeong (25% plan discount) takes one multiplication. On an 89,000-won monthly tariff held for 24 months: 89,000 × 25% × 24 = 534,000 won. If the handset subsidy a shop offers exceeds 534,000 won, take the subsidy; if it falls short, take the discount. The only input is the tariff you intend to use — not the price of the phone — yet in the store the conversation always opens with the handset instalment.
Where the two schemes diverge
A gongsi jiwongeum (publicly posted handset subsidy) cuts the device price once, up front. The plan discount forgoes that subsidy and instead takes 25% off the monthly service charge for the life of the contract. As Korea's Easy Law portal sets out, a subscriber picks one or the other — never both.
Two things shifted when the Mobile Device Distribution Improvement Act was repealed on 22 July 2025. According to Korea.kr, the government policy briefing service, the cap on the extra subsidy retailers could add disappeared, and a previously forbidden combination became legal: taking the 25% plan discount while still collecting a retailer top-up. In exchange, carriers no longer have to publish subsidy figures, so terms now vary shop by shop. ZDNet Korea reported at the one-year mark that subsidy discrimination and pressure toward expensive tariffs had both widened. With the published reference table gone, your own arithmetic is what replaces it.
The number to negotiate against is not the handset price. It is the 534,000 won your own tariff locks in over 24 months.
Which side wins on your tariff?
Because the discount is calculated on the monthly plan charge, the total is fixed as soon as the tariff and the term are known. The table below works out the 12-month and 24-month totals across common price points. The final column is the decision line: if the subsidy on offer, retailer top-up included, clears that figure, take the subsidy.
| Monthly tariff (KRW) | Monthly discount (KRW, 25%) | 12-month total (KRW) | 24-month total (KRW) | Break-even subsidy (KRW, 24-month) |
|---|---|---|---|---|
| 39,000 | 9,750 | 117,000 | 234,000 | 234,000 |
| 55,000 | 13,750 | 165,000 | 330,000 | 330,000 |
| 69,000 | 17,250 | 207,000 | 414,000 | 414,000 |
| 89,000 | 22,250 | 267,000 | 534,000 | 534,000 |
| 109,000 | 27,250 | 327,000 | 654,000 | 654,000 |
One reading jumps out of the table. The break-even line has nothing to do with the price of the device — it is set by the tariff alone, and it tilts toward the plan discount as the tariff rises. Subsidies above 234,000 won are common for someone on a 39,000-won plan; subsidies above 654,000 won for a 109,000-won plan are not. The sales pitch that pushes buyers upmarket on tariffs quietly strengthens the case for the discount.
Three variables the table leaves out
First, the 25% applies only to the plan charge. Handset instalments, instalment interest and add-on service fees are excluded. Budgeting for a quarter off the total invoice will overshoot the real saving.
Second, moving down to a cheaper tariff triggers a clawback. Money Today reported that a subscriber on a 24-month contract who switches to a lower tariff within six months owes a differential settlement charge. Every 24-month total above assumes the same plan is held to the end. If the plan is to sign on an expensive tariff and drop it after a month, recalculate on the tariff you will actually keep.
Third, the two schemes unwind differently on early termination. Take the subsidy and you repay it pro rata against the remaining term; take the discount and you repay the discounts already received. The second grows with time rather than shrinking, so for anyone who replaces handsets often the contract length is itself a cost. A 12-month term halves the benefit — and halves that exposure.
- A tariff of 80,000 won or more, held for the full 24 months
- An unlocked or second-hand handset that was never eligible for a subsidy
- The device is already paid for and only the service charge remains
- Tariffs around 50,000 won — the break-even line drops to 330,000 won
- Older stock models carrying heavy subsidies late in their cycle
- A realistic chance of changing handsets within a year
Who this fits, and who should wait
If the tariff is settled and the 24 months will be seen through, the break-even figure is the only number needed to compare offers. Since the repeal, choosing the plan discount no longer rules out a retailer top-up, so there is no reason to stop negotiating just because the discount was selected.
The case for waiting is equally clear. With no publication requirement, quoted subsidies for the same model on the same tariff now move within days. An offer below the break-even line carries no urgency. And if the real goal is a lower monthly bill rather than a cheaper handset, checking the effective data terms on MVNO tariffs usually saves more than 25% ever will, while splitting lines without changing numbers runs first into the activation differences between eSIM and a physical SIM.
