KRW 10 Million in a Parking Account for Three Months: How Much Interest

Three Months Is Calculated as 92 Days

Interest on a parking account accrues daily. Saying "three months" therefore does not produce a figure; the number of days has to be fixed. Deposit at the start of August and hold for three full months and you get August 31, September 30, and October 31, which is 92 days.

Pre-tax interest is the principal multiplied by the annual rate and the number of days held, divided by 365. Interest income tax of 15.4% is then deducted. That rate is income tax of 14% plus local income tax of 1.4%.

At 4.00% per year, KRW 10 million held for 92 days produces pre-tax interest of KRW 100,821, tax of KRW 15,526, and KRW 85,295 after tax. That is an order of magnitude away from the KRW 400,000 you get by applying 4% straight to KRW 10 million. The period is three months rather than a year, and tax comes out.

What KRW 10 Million Actually Earns

These are the rates verified on August 7, 2026. All stated rates are pre-tax.

Pre-tax interest = principal × annual rate × 92 ÷ 365, with amounts below one won dropped. After-tax interest = pre-tax interest less the tax obtained by multiplying it by 15.4% and rounding to the nearest won.

Comparing only 씨드모아 and 케이뱅크 플러스박스, the gap is KRW 49,045. The headline rates differ by 2.3 percentage points, but over three months the difference in what you receive is under KRW 50,000. A large rate figure does not carry the amount with it when the period is short.

One Month, Three Months, One Year

As the period lengthens, the same rate gap becomes a different amount. This calculation sets preferential conditions aside and uses only 2.0% and 3.0% per year.

Net of interest income tax of 15.4%.

For money you will hold a single month, one extra percentage point is KRW 6,953. Set against the work of opening a new account and meeting preferential conditions, little is left. Over a year the same percentage point becomes KRW 84,600, twelve times as much. Whether to look at the rate first or at the simplicity of the conditions depends on how long you will hold the money.

What the Rate Alone Does Not Show

How far the higher rate reaches

Parking accounts do not pay the same rate on the whole balance, and the direction differs by product. The 씨드모아 small-balance preferential rate applies to balances of KRW 50 million or less, while 케이뱅크 플러스박스 does the reverse and pays 2.20% per year on the portion above KRW 50 million. 카카오뱅크 세이프박스 runs a single 1.60% up to KRW 100 million.

At KRW 10 million all three products sit in their first band. The ranking changes the moment the balance passes KRW 50 million. That is why the amount has to be settled before the product.

How long the preferential rate lasts

The 씨드모아 maximum of 4.00% per year is not a rate you keep. It applies for three months from opening, once per customer. From the fourth month the conditions differ.

For money you will hold exactly three months, that matches. For money held longer, the rate that applies after the preferential period decides what you actually earn.

The rate changes midway

A parking account is a demand deposit, so unlike a term deposit the rate at opening is not fixed to maturity. If the bank lowers the rate, interest is calculated at the lower rate from that day.

The 92-day figures in this article assume the current rate holds for all 92 days. When the base rate is moving, what you actually receive comes in below or above this. For money held long, the comparison is a term deposit, where the rate is fixed to maturity.

When the interest is paid

At the same rate, a product that pays interest daily differs from one that pays monthly. When paid interest is added to the principal, that interest earns interest in turn.

The table above excludes this compounding so that products are compared on the same basis. What you actually receive is slightly more than the table shows.

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