A Korean employee’s health insurance premium is squared up once a year against last year’s pay — the settlement. Article 35(1) of the National Health Insurance Act Enforcement Decree has the employer report, by 31 March each year, the total pay given to each employee member in the previous year and the period worked, and Article 36(1) has the NHIS set the monthly pay as that total divided by the months worked. If the recalculated premium is more than what was collected, the shortfall is collected; if less, the excess is returned (Art. 39(1)). The extra can be paid in up to 12 instalments on the employer’s application (4). Enter last year’s total pay, months worked and the premiums taken each month to see your half of the settlement. The settlement on leaving a job (2) is the same sum.
Rates change each year. This calculator uses the 2026 rate now in force (719 per 10,000) — it fits the settlement of 2026 pay (after the report due by 31 March 2027, our reading) and settlements on leaving a job this year. We did not read the 2025 rate, so don’t use this to check the 2025 settlement already made this year.
1. Monthly pay = last year’s total pay ÷ months worked (Decree Art. 36(1)). 48m won ÷ 12 = 4m won.
2. Recalculated premium − premium already paid (Decree Art. 39(1)). Deducted on 3.5m won but recalculated at 4m won: your half is 215,760 won health + 28,320 won care = 244,080 won extra (our sum).
3. Extra can be split into up to 12 instalments (Decree Art. 39(4)) — when your share is at least the premium floor (20,160 won under the 2026 notice) and the employer applies. 12 instalments of 20,340 won (our sum).
Calculator
Updates as you type. Uses the 2026 health rate (719 per 10,000, Decree Art. 44(1)) and long-term care rate (9,448 per million). Monthly pay drops amounts under 1 won and premiums under 10 won (Act Art. 107); your half is 50/100 of the premium (Act Art. 76(1)) with amounts under 10 won dropped again — our method. It assumes the same amount was taken every month; if your monthly pay changed during the year the real settlement differs. Monthly premiums are kept between the floor of 20,160 won and the cap of 9,183,480 won in Ministry of Health and Welfare Notice No. 2025-222 (in force 1 Jan 2026).
The provisions — text
| Provision | What the text says | Note (our gloss) |
|---|---|---|
| Act Art. 70(1) | An employee member’s monthly pay is calculated on the basis of the pay received. | The base of the sum |
| Decree Art. 35(1) | The employer must report to the NHIS, by 31 March each year, the total pay given to employee members in the previous year (each member’s pay from January to December) and the period worked. | A simplified payment statement filed with the tax office counts as the report (3) |
| Decree Art. 36(1) | The NHIS sets each year’s monthly pay as the reported total divided by the number of months worked at that workplace in the previous year. | An average raise reported by the employer is reflected too (proviso) |
| Decree Art. 39(1) | If the premium originally charged exceeds the recalculated amount, the excess is returned to the employer; if short, the shortfall is collected from the employer. | Settlement between the NHIS and the employer |
| Decree Art. 39(3) | The employer must settle with the employee member the part of the refund or extra payment that the member is to receive or bear. | That is why it shows up in your pay |
| Decree Art. 39(4) | Where the member’s share of the extra is at least the floor of the premium on pay, the NHIS may, on the employer’s application, let it be paid in up to 12 instalments. | Wording as amended 15 Sep 2026 |
Decree Art. 33(1) sets what counts as pay: salary, wages, remuneration, allowances, bonuses and similar payments for work, excluding severance pay, prize money, translation and manuscript fees, and tax-free employment income under the Income Tax Act (some tax-free items are added back). So a large bonus last year raises the total and creates an extra amount at settlement (our gloss).
Three cases — our arithmetic (2026 rates)
| Case (our example) | Recalculated half → settlement | Note (our gloss) |
|---|---|---|
| Total 48m won, 12 months; 125,820 won health and 16,530 won care taken monthly (on 3.5m won) | Monthly pay 4m won → health 143,800 won, care 18,890 won → 244,080 won extra | 17,980 + 2,360 won a month × 12 = 215,760 won health + 28,320 won care; the health extra of 215,760 won is at least the 20,160 won floor, so it can be split if the employer applies — in 12 instalments, 20,340 won each |
| Total 36m won, 12 months, same deductions | Monthly pay 3m won → health 107,850 won, care 14,170 won → 243,960 won back | Lower pay means a refund |
| Leaving: total 24m won, 6 months, same deductions | Monthly pay 4m won → 122,040 won extra | Decree Art. 39(2) — the employer you leave settles |
Your half: monthly pay × 719/10,000 (under 10 won dropped) = monthly premium → half of it (under 10 won dropped). At 4m won that is 287,600 won → 143,800 won; care is 287,600 × 0.9448 ÷ 7.19 = 37,790 won (under 10 won dropped) → 18,890 won. At 3.5m won it is 251,650 → 125,820 won, care 33,060 → 16,530 won. All amounts are our examples.
Settlement on leaving — Decree Art. 39(2)
Article 39(2) has the employer, when employment ends, recalculate the premiums the member paid and settle with the worker before settling with the NHIS. So the settlement for that year is taken from or added to your last pay (our gloss). Decree Art. 35(2)3 also has the employer report total pay to date when some members leave. Enter the months worked that year and the pay received that year for the same sum.
When it can be split — Decree Art. 39(4)
Two conditions together: the member’s share of the extra must be at least the floor of the premium on pay under Decree Art. 32(2)(a), and the employer must apply. The NHIS may then allow up to 12 instalments. The floor is an amount the Minister notifies between 50/1,000 and under 85/1,000 of the average premium on pay two years before, and Article 3(1) of the Notice on the Monthly Cap and Floor of Health Insurance Premiums (Ministry of Health and Welfare Notice No. 2025-222, in force 1 January 2026) sets it at 20,160 won. The calculator tests the condition by comparing your half of the health extra with 20,160 won — long-term care is not compared (our reading). The settlement for 2026 is made after the report due by 31 March of the next year (Decree Art. 35(1)), so if the notice has changed by then, the new floor applies (our reading). Article 2(1) of the same notice caps the premium on pay at 9,183,480 won (your half 4,591,740 won). Details are in the NHIS articles of association (5).
Checklist
- ☐ Last year’s total pay — bonuses in, severance and tax-free employment income out (Decree Art. 33(1))
- ☐ Months worked at that employer last year
- ☐ Health and long-term care deductions on your payslip
- ☐ A large extra? Ask whether the employer applied to split it
- ☐ Check the settlement in your last pay when you leave
Questions that remain
Does the settlement change this year’s premium too?
Yes. Article 36(1) sets “each year’s monthly pay” by the same sum, so the new monthly pay from last year’s total becomes the base for this year’s monthly premium (our reading). All the premiums on a salary are in the take-home pay calculator.
What about income other than pay?
Income not counted as pay above 20m won a year draws a separate non-salary premium, billed to you apart from this settlement — non-salary income premium calculator.
What if the extra isn’t paid?
The employer pays premiums to the NHIS (Act Art. 77(1)1). After the due date a late charge of 1/1,500 a day applies — see the health insurance late charge calculator.
How is monthly pay set in the month you join, or for an owner with no salary?
Decree Art. 37 sets it for someone who joins or changes workplace: pay fixed per year, month, week and so on is pay ÷ total days in that period × 30; daily, hourly or piece pay uses the average of people doing the same work for the same pay in the previous month; otherwise the average for the same work. An employer who draws no pay is set under Art. 38 from that year’s business income (or their own report if there is no evidence), filed by 31 May (30 June for those under certified filing), and applied from June to the next May (July to June). If that is lower than the highest-paid worker’s figure, the worker’s figure applies; with no filing and no evidence, or a confirmed amount of 0 or less, the workers’ average applies (Art. 38(3); checked 9 November 2026). This calculator only works out the settlement difference from a monthly pay figure already set.
Sources
- Korea Law Information Center — National Health Insurance Act — text (in force 8 Oct 2026, Act No. 21522; checked 9 November 2026). Arts. 70(1)(3)(4), 76(1), 77(1), 107.
- Enforcement Decree — text (in force 1 Oct 2026, Presidential Decree No. 36675; checked 9 November 2026). Arts. 32(2)(a), 33(1), 35(1)–(3), 36(1), 39(1)–(5), 44(1).
- Korea Law Information Center — Notice on the Monthly Cap and Floor of Health Insurance Premiums — text (in force 1 Jan 2026, Ministry of Health and Welfare Notice No. 2025-222; checked 9 November 2026). Art. 2(1) (cap on the premium on pay, 9,183,480 won), Art. 3(1) (floor, 20,160 won).
- Long-Term Care Insurance for the Elderly Act Art. 9 and Decree Art. 4 — text (checked 9 November 2026). 9,448 per million.
- Not read. The 2027 notice (the floor at the time of the 2026 settlement), NHIS articles on settlement and instalments, and the 2025 rate. (Decree Arts. 37–38 checked 9 November 2026: in force 1 Oct 2026, Decree No. 36675.)
- Added by us. The calculator, the three cases, the rounding order for your half and the notes column.
Where to check further
- Your payroll team — the settlement breakdown and any instalment application.
- National Health Insurance Service — the confirmed monthly pay and settlement.
Written on 9 November 2026. The provisions are taken from the Korea Law Information Center; the arithmetic and glosses are ours.
