Interim Income Tax Prepayment in Korea: Deadline, Who Pays, and Installments (2026)

For foreign nationals: some of these rules apply differently depending on whether you are a resident or a non-resident for Korean tax purposes. Check your residency status before relying on this article.

The interim prepayment of comprehensive income tax (종합소득세 중간예납) is due November 30, 2026. The notice amount is one-half of the interim prepayment base amount (중간예납기준액) for the preceding tax period. It applies to individuals with business income. If your first-half results fell this year, you can file an estimate. If the tax is over KRW 10 million, you can pay in installments.

What interim prepayment is: tax you pay early in November

Comprehensive income tax is finalized in May of the next year for the full year. But individuals with business income pay part of it early, in November. This is the interim prepayment. The amount you prepay is deducted from the determined tax at the final filing in May of the next year.

Item	Details
Period covered	January 1 ~ June 30
Notices mailed	Early November
Payment deadline	November 30 (a Monday in 2026)
Notice amount	One-half of the interim prepayment base amount for the preceding tax period

Who does not make the interim prepayment

You do not make the interim prepayment in these cases.

You started your business this year.
You only have interest, dividend, salary, pension, or other income.
The interim tax to be notified is under KRW 500,000.

Estimate filing: if your first half was weak

The notice amount is based on last year’s results. If your results fell sharply in the first half of this year, you may prepay more tax than you actually owe. In that case, you can file and pay an amount calculated from your actual January~June results (the estimated interim tax, 중간예납추계액).

You can choose this if the estimate is less than 30% of the notice base amount.
Once you file the estimate, the notice you received no longer applies. You pay the amount you filed.
The estimate must be based on your first-half books. It helps to organize your first-half closing records before November.

Installments: over KRW 10 million, split over 2 months

If the tax due is over KRW 10 million, you can pay part of it in installments within 2 months after the deadline.

Tax due	Amount you can pay in installments
Over KRW 10 million up to KRW 20 million	The part over KRW 10 million
Over KRW 20 million	Up to 50% of the tax

Missing the deadline: what people overlook

Missing the deadline adds a penalty tax (가산세). Even if you did not receive the notice, you can look up the notice on Hometax (홈택스) or the Sontax (손택스) mobile app. It is worth checking once during November.
Paying the interim prepayment does not finish your May filing. In May, you file again based on the full year’s income. The interim tax you already paid is deducted.

When you can do it yourself · When to hand it over

You can handle it yourself if

You pay the notice amount as printed, by the deadline.
The amount is over KRW 10 million and you only need to apply for installments.

Better to hand it over if

Your first-half results dropped sharply and you need to decide whether to file the estimate.
You missed expenses or deductions when you filed in May.

Barun Tax & Accounting handles comprehensive income tax filing and interim prepayment estimate filing for foreign residents and foreign-owned companies. We reply to emails within one business day. contact@barun-tax.com · KakaoTalk · +82-10-2701-6199

Frequently asked questions

When is the interim prepayment of comprehensive income tax due?

Notices are mailed in early November. The deadline is November 30. In 2026, November 30 is a Monday.

How is the interim prepayment notice amount set?

It is one-half of the interim prepayment base amount for the preceding tax period. The period covered is January 1 to June 30. The amount you prepay is deducted from the determined tax at the final filing in May of the next year.

Are there cases where I do not have to make the interim prepayment?

You do not make the interim prepayment if you started your business this year, if you only have interest, dividend, salary, pension, or other income, or if the interim tax to be notified is under KRW 500,000.

My sales fell in the first half of this year. Do I still have to pay the notice amount?

If the estimated interim tax, calculated from your actual January~June results, is less than 30% of the notice base amount, you can file and pay the estimated amount instead. Once you file the estimate, the notice you received no longer applies.

Can I pay the interim prepayment in installments?

If the tax due is over KRW 10 million, you can pay part of it in installments within 2 months after the deadline. For tax over KRW 10 million up to KRW 20 million, the installment amount is the part over KRW 10 million. For tax over KRW 20 million, it is up to 50% of the tax.

This article is general guidance based on Korean tax law as of the date written. It is not tax advice for your specific situation. Please consult us before acting on it.

← All posts