Miss the due date for a Korean health insurance premium and a late charge follows. Article 78(1) of the National Health Insurance Act makes a month’s premium due by the 10th of the following month, and Article 80 charges a late fee for each day that passes from the day after the due date. For premiums it starts at 1/1,500 of the arrears a day and stops once at 20 per 1,000 (2%); from 30 days after the due date it adds 1/6,000 a day up to a final cap of 50 per 1,000 (5%). Enter the arrears, the due date and the day you pay to get the charge to the won. The rates match the National Pension late charge (National Pension Act Art. 97), so it also helps when both bills arrive together.
1. Due by the 10th of the next month (Act Art. 78(1)). October’s premium is due on 10 November (our example).
2. First 30 days: 1/1,500 a day, capped at 2% (Art. 80(1)1). 30 ÷ 1,500 = 2%, so the cap arrives on day 30 exactly.
3. Then 1/6,000 a day, final cap 5% (Art. 80(2)1). The remaining 3% takes 180 days, 210 days in all, then nothing more (our sum). On 200,000 won of arrears the most is 10,000 won.
Calculator
Updates as you type. Dates as YYYY-MM-DD. “Days past the due date” is the payment day minus the due date (the day after the due date is day 1) — our method. Amounts under 10 won are dropped (Act Art. 107 → National Treasury Management Act Art. 47). If the due date falls on a Saturday or holiday the real date may differ, so use the date on your bill.
Article 80 — text
| Stage | What the text says | Note (our gloss) |
|---|---|---|
| (1)1 (premiums) | If not paid by the due date, for each day that passes from the day after the due date, 1/1,500 of the arrears; the charge may not exceed 20/1,000 of the arrears. | About 0.0667% a day — 2% at 30 days |
| (2)1 (premiums) | If still unpaid, from the day 30 days after the due date has passed, for each day, 1/6,000 of the arrears added to the charge in (1); the charge (including (1)1) may not exceed 50/1,000. | A quarter of the speed, up to 5% in total |
| (1)2 and (2)2 (other amounts) | First 1/1,000 a day, capped at 30/1,000; after 30 days 1/3,000 a day added, total cap 90/1,000. | E.g. recovered unjust benefits — selectable in the calculator |
| (3) | Where there is a natural disaster or another unavoidable reason set by Ministry ordinance, the charge may not be collected. | Reasons are in Rule Art. 51 (below) |
Rule Art. 51 lists five such reasons: arrears caused by war or incident; a charge at or below an amount in the NHIS articles of association; arrears that cannot be collected because a workplace or private school closed; arrears caused by fire damage; and other cases the Minister accepts. We did not read the amount in the articles. Separately, Act Art. 106 says amounts under 2,000 won per item are not collected; how that applies to late charges is the NHIS’s call, so the calculator only flags it.
In days — our arithmetic (200,000 won of premiums unpaid)
| Days past due | Rate so far → charge | Note (our gloss) |
|---|---|---|
| 1 day | 0.067% → 130 won | 133.3 won, under 10 won dropped |
| 15 days | 1% → 2,000 won | The same speed each day |
| 30 days | 2% → 4,000 won | First cap |
| 35 days (paid 15 December) | 2.083% → 4,160 won | 5 days × 1/6,000 after day 30 |
| 120 days | 3.5% → 7,000 won | 90 days × 1/6,000 = 1.5% |
| 210 days and after | 5% → 10,000 won | Final cap — nothing more |
30 ÷ 1,500 = 20/1,000, so the first stage hits its cap on day 30; the remaining 30/1,000 takes 30 × 6,000 ÷ 1,000 = 180 days, 210 days in all. For other amounts, 30/1,000 ÷ 1/1,000 = 30 days and 60/1,000 ÷ 1/3,000 = 180 days, so they also stop at 9% after 210 days (our sum). The 200,000 won and 10 November due date are our example.
When the due date can move — Rule Art. 48-2
Act Art. 78(2) lets the NHIS, on application, extend the due date by up to one month from the due date where there is a reason such as late delivery of the bill. Rule Art. 48-2(1) lists the reasons: the bill arrived after the due date through no fault of the payer; payment by automatic transfer failed because of a network fault or similar; and other cases the Minister accepts. Apply with the extension form within one month of the due date (2). Rule Art. 48 has the NHIS issue bills 10 days before the due date.
Long-term care follows the same sum
Article 11 of the Long-Term Care Insurance for the Elderly Act applies NHI Act Arts. 76 to 86 to paying and collecting the care premium. Article 80 is inside that range, so we read the same late charge as applying to an unpaid care premium (our reading). Entering both together gives the same method because the rates match — though dropping amounts under 10 won separately can shift the result by a few tens of won.
Checklist
- ☐ Check the due date on the bill — usually the 10th of the next month
- ☐ Bill arrived late? Apply within a month to extend
- ☐ Same for an automatic transfer that failed
- ☐ Behind? Act within 30 days — 2% by day 30, then up to 5% by day 210
- ☐ The non-salary premium can be paid quarterly (proviso to Act Art. 78(1))
Questions that remain
Does it slow down after 30 days?
The daily speed falls from 1/1,500 to 1/6,000, but the total keeps rising to 5%. It is not “less” but “more, more slowly” (our gloss).
Do employees pay late charges?
The premium on pay is deducted from salary and paid by the employer (Act Art. 77(1)1, (3)), so if the employer pays late the employer owes the charge (our reading). The premium on non-salary income is paid by you, so lateness there is yours.
Is it the same as the National Pension late charge?
The rates are the same — National Pension Act Art. 97 also uses 1/1,500 and 20/1,000, then 1/6,000 and 50/1,000 after 30 days. The day table is in pension due date and late charge.
What happens if it stays unpaid?
National Health Insurance Act Art. 81 sets the order (checked 9 November 2026). The NHIS may send a reminder with a deadline — where there are two or more employers or household members, a reminder to one counts for all (1) — giving 10 to 15 days to pay (2). If still unpaid, with the health minister’s approval it can collect as for national tax arrears (3), but must first send a notice of the arrears, the property that can be seized, the planned seizure and the bar on seizing small financial assets (4; not in urgent cases such as a company winding up). Public sale of seized property can be handed to KAMCO (5). The late charge runs under Art. 80 separately from the reminder (our reading).
Sources
- Korea Law Information Center — National Health Insurance Act — text (in force 8 Oct 2026, Act No. 21522; checked 9 November 2026). Arts. 77(1)(3), 78(1)(2), 80(1)–(3), 106, 107.
- Enforcement Rule — text (in force 28 Sep 2026, Ordinance No. 1202; checked 9 November 2026). Arts. 47, 48, 48-2, 51.
- Long-Term Care Insurance for the Elderly Act Art. 11 — text (in force 26 May 2026, Act No. 21690; checked 9 November 2026).
- National Treasury Management Act Art. 47(1) — amounts under 10 won not counted (checked 9 November 2026).
- Korean law database — National Health Insurance Act Art. 81 — source (in force 8 Oct 2026, Act No. 21522; checked 9 November 2026). Reminder (10–15 days), enforcement, advance notice, public sale by KAMCO.
- Not read. The amount in the NHIS articles below which no charge is collected, what happens when a due date falls on a holiday (Civil Act period rules).
- Added by us. The calculator, the day table, the 210-day sum and the notes column.
Where to check further
- National Health Insurance Service — actual arrears and charges, extension requests.
- Local member premiums — local member premium calculator.
Written on 9 November 2026. The provisions are taken from the Korea Law Information Center; the date and amount arithmetic is ours.
