If your South Korean national health insurance premium is higher than usual in November 2026, the first step is to determine whether the increase comes from newly updated income and property data or a reconciliation of premiums previously adjusted based on your income. The main groups that should check are regionally insured subscribers and employee-insured subscribers who pay additional premiums on income earned outside their regular salaries. Depending on the reconciliation results, you may owe an additional payment or receive a refund.guidance from South Korea's National Health Insurance Service (NHIS) indicates that November is the annual period when new assessment data are applied to health insurance premium calculations. At the same time, subscribers who previously requested income-based premium adjustments may see reconciliation results reflecting a recalculation of their earlier premiums.
These two procedures have different purposes and calculation bases. Therefore, a higher November bill does not necessarily mean that you owe an additional payment because of income reconciliation.
Why South Korean Health Insurance Premiums May Change in November
Every November, the NHIS incorporates updated income and property information received from government agencies into its premium calculations. If a subscriber's assessed income or property tax assessment base has changed, the resulting premium may differ from the previous month's amount.
The newly updated assessment data generally apply from November of the current year through October of the following year.
The information used depends on the subscriber's insurance category:
Regionally insured subscribers: Income and property data used to calculate their health insurance premiums. In South Korea, this category generally covers people insured outside the employee-based system.
Employee-insured subscribers paying additional income-based premiums: Information about income earned outside the remuneration they receive from their employers.
The additional income-based premium, known in Korean as *sodeuk-woraek boheomryo* (소득월액보험료), is a separate national health insurance premium that certain employee-insured subscribers must pay on non-salary income when specified conditions are met.
An important distinction is that updating assessment data is not the same as imposing a uniform premium increase on all subscribers.
Even after new information is applied, an individual's premium may increase or decrease depending on the factors used in the calculation.
Updated Assessment Data vs. Income Adjustment and Reconciliation
Updating income data changes the basis used to calculate premiums for future billing periods. Income reconciliation, by contrast, recalculates previously adjusted premiums using subsequently confirmed income information.
Income reconciliation is relevant when a subscriber has requested a premium adjustment because of reduced income or similar circumstances.
The differences between these procedures are summarized below.
| Category | Updated Assessment Data | Income Adjustment and Reconciliation |
|---|---|---|
| Purpose | Calculate premiums using newly available information | Recalculate premiums that were previously adjusted |
| Main affected subscribers | Regionally insured subscribers and those subject to additional income-based premiums | Subscribers subject to income adjustment and reconciliation |
| Timing | Every November | Generally November of the year following the adjustment |
| Calculation basis | Newly obtained income, property, and other assessment information | Income confirmed by the National Tax Service and other relevant authorities |
| Result | Changes to subsequent premiums | Additional payment or refund |
Consider someone whose November 2026 health insurance bill has increased.
If that person has never requested a premium adjustment, the first step should be to check the newly applied income and property data.
However, if the person received a premium adjustment in 2025 because of reduced business income or similar circumstances, they should check whether the November 2026 bill includes a reconciliation of that earlier adjustment.
The actual reconciliation period may vary depending on when the adjustment was requested and when it took effect.
If Your Premium Was Reduced in 2025, What Happens in November 2026?
If you received a South Korean national health insurance premium adjustment in 2025 because your income had decreased, the NHIS may, in principle, reconcile the adjusted premiums in November 2026 using confirmed income information.
The premium adjustment system is designed to reflect reduced income by adjusting a subscriber's current financial burden. However, the final income for the relevant year may not yet have been determined when the adjustment is made.
Later, the NHIS recalculates the premiums using income confirmed by the National Tax Service and other authorities, then compares the recalculated amount with the premiums already paid.
Importantly, receiving a premium reduction in 2025 does not automatically mean that an additional payment will be required in November 2026.
The outcome depends on the difference between the premiums actually paid and the premiums recalculated using confirmed income.
In addition, even if only one type of income was adjusted, such as business income or employment income, the reconciliation rules require relevant income categories to be combined in the calculation.
Therefore, a decrease in income from a particular business does not necessarily mean that the overall reconciliation will result in a refund.
How Additional Payments and Refunds Are Calculated
Whether a subscriber owes an additional payment or receives a refund depends on which amount is greater: the premiums already paid or the premiums recalculated using confirmed income.
The NHIS explains that its income reconciliation procedure compares these amounts and either charges or refunds the difference.
Consider the following hypothetical calculations.
Example 1: An Additional Payment of KRW 300,000
Suppose the premiums paid during the relevant adjustment period in 2025 totaled KRW 1,200,000, while the premiums recalculated using confirmed income amounted to KRW 1,500,000.
Author's calculation:
KRW 1,500,000 − KRW 1,200,000 = KRW 300,000 additional payment
Because the amount already paid is lower than the recalculated premium, the subscriber must pay the difference.
Example 2: A Refund of KRW 300,000
Now suppose the subscriber paid KRW 1,500,000 during the adjustment period, but the recalculated premiums totaled KRW 1,200,000.
Author's calculation:
KRW 1,500,000 − KRW 1,200,000 = KRW 300,000 refund
Because the amount already paid exceeds the recalculated premium, the difference is refundable.
These examples are hypothetical and are intended only to illustrate the reconciliation mechanism. Actual reconciliation requires consideration of each person's income, adjustment period, and premium assessment conditions. The example amounts cannot be applied directly to individual cases.
Can You Owe Additional Premiums Even If Your Income Decreased?
Yes. A decrease in income does not necessarily mean that the reconciliation will produce a refund.
An additional payment may arise if the premiums recalculated using confirmed income exceed the premiums paid under the earlier adjustment.
For example, even if someone closed a business, they may still have earned income earlier in the same year. The amount reflected when the premium adjustment was granted may differ from the amount calculated using final confirmed income.
This is particularly important for people who have both business income and employment income. A reduction in one income category alone may not determine the overall reconciliation outcome.
Therefore, if you receive an additional payment notice despite a decrease in income, compare the income information used when you applied for the adjustment, your subsequently confirmed income, and the premiums you actually paid.
How to Check Your November 2026 Premium and Reconciliation Details
If your November bill differs from your usual amount, you can review it through the NHIS premium inquiry services and the services related to income adjustment and reconciliation.
Follow these steps:
1. Compare October and November premiums: Identify the difference between the current premium and the previous month's amount.
2. Review newly applied assessment data: Check whether the income, property, or other information used to calculate your premium has changed.
3. Check previous adjustment applications: Determine whether you requested a premium adjustment in an earlier year because of business closure, temporary business suspension, retirement, termination of an appointment or contract, or similar circumstances.
4. Review reconciliation details: Check the reconciliation period, confirmed income, recalculated premiums, and any additional payment or refund amount.
5. Contact the NHIS if the difference is unclear: Request an explanation of the assessment data and reconciliation calculations.
The personal civil services section of the NHIS website provides information about premium inquiries and services for applying for or reviewing income adjustments and reconciliations.
Related services are also available through the NHIS mobile application, *The Health Insurance* (The건강보험).
The NHIS customer service number in South Korea is 1577-1000. Call charges apply to the caller.
Individual premium amounts for November 2026 must be verified through actual billing notices or account inquiries.it cannot be assumed that the November reconciliation results have been finalized for every subscriber.
Who Can Apply for an Income-Based Premium Adjustment?
People whose business income or employment income has decreased, or whose income-generating activities have stopped, may be eligible to apply under South Korea's income-based national health insurance premium adjustment and reconciliation system.
The NHIS provides adjustment procedures for people whose income has decreased because of temporary business suspension, permanent business closure, retirement, termination of an appointment or contract, or similar circumstances, subject to supporting documentation.
Typical documents include an income reconciliation assessment consent form, a certificate confirming business closure or suspension, and a certificate of retirement or termination of an appointment or contract.
However, some documents may be waived when the NHIS can independently verify the relevant circumstances, such as a registered business closure or suspension.
Applying for an adjustment does not guarantee that the final premium will be permanently reduced. A subsequent reconciliation may be conducted using confirmed income.
In addition, if an earlier income adjustment allowed someone to qualify as a dependent under the health insurance system or receive benefits tied to premium assessment criteria, the reconciliation outcome may result in changes to eligibility or recovery of previously granted benefits.
Before applying, it is important to verify when your income decreased, when you submitted the adjustment application, and which period will actually be subject to reconciliation.
Does a Higher November Bill Mean Your Monthly Premium Will Stay Higher?
The most important point is not to treat the entire billed amount as a single premium increase.
If newly updated income and property data have changed the basis for calculating your premiums, the change may affect subsequent monthly bills.
By contrast, a reconciliation amount resulting from the recalculation of previously adjusted premiums represents a difference relating to an earlier period.
Therefore, if your November bill includes a reconciliation amount, you should not assume that the entire amount represents the basic premium you will have to pay every month going forward.
The actual billing and payment arrangements for reconciliation amounts must be checked against your individual records.
The most reliable way to distinguish an ongoing change in your premium from a difference arising from an earlier reconciliation is to review the current month's premium assessment details and the income reconciliation statement separately.
Frequently Asked Questions About November Health Insurance Premiums
Does Every Regionally Insured Subscriber Pay More in November?
No. The fact that new assessment data are applied every November does not mean that premiums increase for every regionally insured subscriber in South Korea. The result depends on each person's income, property, and premium assessment conditions.
Can My Premium Increase Even If I Never Applied for an Income Adjustment?
Yes. Even without an income adjustment or reconciliation, your premium may change when newly updated income and property information is incorporated into the calculation.
If My Income Decreased, Will I Automatically Receive a Refund?
No. Refund eligibility depends on the difference between the premiums already paid and those recalculated using confirmed income, rather than simply on whether income decreased. A refund may be due if the amount paid exceeds the recalculated premiums.
Do These November Reconciliation Rules Apply to All Employees?
No. The relevant procedures may apply to employee-insured subscribers who pay additional income-based premiums on non-salary income and who meet the conditions for income adjustment and reconciliation. The premiums deducted from every employee's salary are not all reconciled in the same way in November.
What to Check When You Receive Your November 2026 Health Insurance Bill
When you receive your November 2026 national health insurance bill in South Korea, first compare the current month's premium with the October amount. Then check separately whether the bill includes a reconciliation amount arising from a previous income-based adjustment.
Distinguishing these two amounts is essential to determining whether the basis for calculating your ongoing premiums has changed or whether you are paying or receiving a difference relating to premiums from an earlier period.