A Korean employee’s health insurance premium is not charged on salary alone. Article 69(4) of the National Health Insurance Act splits an employee member’s monthly premium into two lines, the premium on monthly pay and the premium on non-salary monthly income, and Article 71(1) charges the second one when income earned outside the salary exceeds an amount set by Presidential Decree. Article 41(4) of the Enforcement Decree sets that amount at 20 million won a year. The formula is (annual non-salary income − 20m won) × 1/12, and Article 44(2) of the Enforcement Rule counts wage and pension income at 50%. We multiply by the premium rate of 719 per 10,000 (7.19%) and add long-term care insurance. Employees with rental or business income, pensions, or interest and dividends can see a rough figure before the bill arrives.
1. The threshold is 20m won a year (Decree Art. 41(4)). At 20m won or less outside your salary there is no non-salary premium.
2. 1/12 of the excess × 7.19% (Act Art. 71(1), Decree Art. 44(1)). Business income of 30m won gives a monthly income of 833,333 won and a health premium of 59,910 won (our sum).
3. Wages and pensions count at 50%; interest and dividends of 10m won or less are left out (Rule Art. 44(1)–(2)). You pay it, not your employer (Act Art. 76(2)).
Calculator
Updates as you type. Enter tax-law income amounts (after necessary expenses) (Rule Art. 44(1)); leave out tax-free income (Decree Art. 41(1)). Monthly income drops amounts under 1 won and the premium drops amounts under 10 won (Act Art. 107 → National Treasury Management Act Art. 47). The health premium stops at the monthly cap of 4,591,740 won (Decree Art. 32(1)(b) → Ministry of Health and Welfare Notice No. 2025-222, Art. 2(2), in force 1 Jan 2026). Long-term care is our sum: the health premium × 0.9448 ÷ 7.19.
The provisions — text
| Provision | What the text says | Note (our gloss) |
|---|---|---|
| Act Art. 71(1) | An employee member’s non-salary monthly income is assessed, where income other than the pay counted in monthly pay exceeds an amount set by Presidential Decree, by evaluating the value of the formula as set by Ministry ordinance. Formula: (annual non-salary income − amount set by Presidential Decree) × 1/12 | Only the excess counts, not the whole 20m |
| Decree Art. 41(4) | “An amount set by Presidential Decree” in Article 71(1), both outside and inside the formula, means 20 million won a year. | Threshold and deduction are the same 20m |
| Rule Art. 44(2) | Interest, dividend, business and other income at the full amount; wage and pension income at 50 per 100. Each type is the formula result multiplied by that type’s share of annual non-salary income. | The 20m test uses the total before the 50% (the formula comes first) |
| Rule Art. 44(1) proviso | Where income under Income Tax Act Art. 14(3)6 is 10 million won or less, that interest and dividend income is not added. | The calculator drops interest and dividends totalling 10m or less (our reading) |
| Decree Art. 44(1) | The premium rate for employee members and for local members is each 719 per 10,000. | 7.19% — the non-salary part is not split with the employer |
Article 76(2) says the non-salary premium is borne by the employee member, and Article 77(1)2 says the employee member pays it. The premium on pay is split half and half with the employer (Art. 76(1)), but this part is 100% yours. It is not taken from your pay; the NHIS bills it separately (our gloss).
Which year’s income — Decree Art. 41(3)
Article 41(3) of the Decree sets the timing. For January to October the NHIS uses data from two years before the premium year (pension income only from the year before); for November and December it uses the year before. So November and December 2026 use 2025 income, and January to October 2027 use 2025 income again (pensions 2026) (our example). Enter the income of the year the bill uses, not this year’s.
If income fell because of closure or a change in results, Decree Art. 41-2(1) lets you apply, with proof, to have the premium adjusted to income at the time of charging. Once that year’s income is confirmed the NHIS settles again (4); a shortfall is collected, payable in up to 12 instalments (5)–(6), and an overpayment is refunded (7).
You can also pay quarterly. The proviso to Act Art. 78(1) allows the non-salary premium to be paid by quarter, and Rule Art. 47 says that if you apply by the last day of the month before the quarter, the due date is the 10th of the month after the quarter ends.
Five cases — our arithmetic
| Case (our example, a year) | Monthly income → premium | Note (our gloss) |
|---|---|---|
| Rental business income 30m | 833,333 won → health 59,910 won + care 7,870 won = 67,780 won | 813,360 won over a year |
| Public pension 30m | 416,666 won → health 29,950 won + care 3,930 won = 33,880 won | Pensions at 50%, so about half the business case |
| Business 15m + pension 15m | 625,000 won → health 44,930 won + care 5,900 won | The excess is shared by type; only the pension share is halved |
| Interest & dividends 9m + other 15m | 0 won | Interest and dividends of 10m or less drop out, leaving 15m |
| Interest & dividends 12m + other 15m | 583,333 won → health 41,940 won + care 5,510 won = 47,450 won | Above 10m the whole amount goes in (our reading) |
Order of the sum: income counted − 20m → ÷ 12 → split by income type, halving only wages and pensions → total (under 1 won dropped) × 7.19% (under 10 won dropped) → long-term care = that × 0.9448 ÷ 7.19 (under 10 won dropped). The order follows the formula (Act Art. 71(1)) and then the evaluation (Rule Art. 44(2)); that is our method.
Long-term care is added on top
Article 9(1) of the Long-Term Care Insurance for the Elderly Act sets the care premium as the premium calculated under NHI Act Art. 69(4) multiplied by the ratio of the care rate to the health rate, and Article 4 of its Decree sets the care rate at 9,448 per million (0.9448%). The non-salary premium is also an Article 69(4) premium, so the calculator adds the health premium × 0.9448 ÷ 7.19. Article 8(2) has the two collected together but billed separately, so they show as two lines on the bill.
Checklist
- ☐ List income outside your pay by type — income amounts, not receipts
- ☐ Does the total exceed 20m? — wages and pensions before the 50%
- ☐ Are interest and dividends 10m or less?
- ☐ Which year’s income the month uses (Jan–Oct two years back, Nov–Dec one year back)
- ☐ Income fell sharply? Apply for an adjustment (Decree Art. 41-2)
Questions that remain
Does going 1 won over 20m make the premium jump?
No. The formula subtracts 20m, so only the excess counts. At 20,000,001 won the non-salary monthly income rounds down to 0 won (our sum). That differs from tests where crossing the line changes everything, such as dependant status — see the dependant checker.
Is there a cap?
Yes. Decree Art. 32(1)(b) sets the cap on the non-salary premium as an amount the Minister notifies, considering 15 times the average premium on pay two years before. Article 2(2) 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 the cap on an employee’s premium on non-salary income at 4,591,740 won. The calculator stops the health premium there and works long-term care from the capped amount — at the cap, 4,591,740 won health + 603,370 won care = 5,195,110 won a month (our sum). With only income counted in full, such as business or interest income, the cap is reached once counted income is 786,356,060 won a year or more (non-salary monthly income 63,863,005 won × 7.19% = 4,591,750 won; our sum). Article 3 of the same notice sets floors only for the premium on pay and for local members, not for the premium on non-salary income.
What happens when I retire?
Losing employee status makes you a local member, and the premium is reworked from all income plus property — see the local member premium calculator.
What if I pay late?
Premiums are due by the 10th of the following month (Act Art. 78(1)); after that a late charge of 1/1,500 a day applies — health insurance late charge calculator.
Sources
- Korea Law Information Center — National Health Insurance Act — text (in force 8 Oct 2026, Act No. 21522; checked 9 November 2026). Arts. 69(4), 71(1), 73(1), 76(2), 77(1), 78(1), 107.
- Enforcement Decree — text (in force 1 Oct 2026, Presidential Decree No. 36675; checked 9 November 2026). Arts. 32, 41(1)(3)(4), 41-2, 44(1).
- Enforcement Rule — text (in force 28 Sep 2026, Ministry of Health and Welfare Ordinance No. 1202; checked 9 November 2026). Arts. 44(1)(2), 47.
- Long-Term Care Insurance for the Elderly Act Arts. 8–9 and Decree Art. 4 — text (Act No. 21690 in force 26 May 2026; Decree No. 36325 in force 12 May 2026; checked 9 November 2026). 9,448 per million.
- 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(2) (cap on an employee’s premium on non-salary income, 4,591,740 won), Art. 3 (floors only for the premium on pay and for local members).
- National Treasury Management Act Art. 47(1) — amounts under 10 won are not counted (version in force 2 Jan 2026; checked 9 November 2026).
- Not read. NHIS articles of association, and the Income Tax Act provisions defining each income amount.
- Added by us. The calculator, the five cases, the notes column and the order of the sum.
Where to check further
- National Health Insurance Service — the billed amount, quarterly payment and adjustment requests.
- Side income and tax — side jobs for employees.
Written on 9 November 2026. The provisions are taken from the Korea Law Information Center; the arithmetic and glosses are ours.
