Parking Account Interest: One Day, One Month, Three Months

Interest Is Calculated for as Long as the Money Is Held

A parking account is an instant-access deposit, so leaving money in for a single day still has that period's interest calculated.

The method is simple. Multiply the principal by the annual rate, divide by 365, then multiply by the days actually held. KRW 10 million at 4.00% per year for one day gives KRW 10 million × 4.00% ÷ 365, or about KRW 1,095 pre-tax.

It is not structured like a time deposit, where the same rate requires holding to the end of the agreed term. Withdraw after a few days and interest is still calculated for the period actually held.

씨드모아통장 settles interest on the fourth Friday of each month and pays it into the account the following day.

After-Tax Interest by Amount

These figures assume the preferential conditions on 씨드모아 (small-balance preferential) are met and 4.00% per year applies. One month is taken as 30 days and three months as 92 days.

Calculated by applying 4.00% per year (pre-tax, as of July 2, 2026) throughout the holding period and deducting interest income tax of 15.4%. The figures assume the balance does not change and that every preferential condition is met, so they can differ slightly from what is actually paid.

To try your own amount and period, use the interest calculator.

Interest Income Tax Is 15.4%

Deposit interest carries income tax of 14% plus local income tax of 1.4%, so 15.4% is withheld at the ordinary tax rate. The bank deducts the tax first when paying interest and deposits the remainder.

For a quick after-tax figure, multiply the pre-tax interest by 0.846.

KRW 10 million held for 92 days at 4.00% per year, for example, produces pre-tax interest of KRW 100,821. Deducting KRW 15,526 of tax leaves after-tax interest of KRW 85,295.

Compare products on the same pre-tax rate, and switch to the after-tax figure when checking what you will actually receive.

Where interest and dividends for a year exceed a set amount, global taxation of financial income can apply. The rate breakdown is in interest income tax of 15.4%, and the calculation above KRW 20 million is in global taxation of financial income.

The Calculation Changes Once the Preferential Rate Ends

The maximum 4.00% per year on 씨드모아통장 does not keep applying. On both products the preferential rate applies for three months from opening, once per customer, after which the base rate applies according to the balance band.

The base rate is 1.80–2.00% per year, pre-tax.

Take KRW 10 million left for a year with no deposits or withdrawals, with 4.00% per year for the first 92 days and 2.00% for the remaining 273, as a simple calculation. Interest paid along the way earning further interest is excluded.

The first 92 days produce KRW 100,821 pre-tax. Over the following 273 days at 2.00% per year, KRW 149,589 accrues. Together that is KRW 250,410 pre-tax and about KRW 211,847 after tax at the ordinary rate.

After tax that is about KRW 211,847. A calculation excluding the additional interest that would arise from redepositing the interest paid each month.

Calculating instead as though 4.00% ran the whole year gives KRW 400,000 pre-tax and KRW 338,400 after tax. Against the simple calculation that reflects the actual preferential period, the after-tax gap is about KRW 120,000.

So for money you will hold longer than three months, adding the rate that applies after the preferential period is more accurate than reading a year of interest off the top rate alone.

When Comparing With Other Accounts

Start with how many months the preferential rate lasts. The same 4.00% per year applied for three months and applied without a time limit produce different interest over a long holding period.

Matching the periods matters when comparing. Where the preferential period is three months, as with 씨드모아, calculating other products on the same 92-day basis makes the difference easy to see. Products lined up that way are in KRW 10 million in a parking account for three months.

How far up the higher rate reaches also needs checking. 씨드모아 (small-balance preferential) applies the preferential rate to amounts of KRW 50 million or less, while 씨드모아 (large-balance preferential) applies it to the entire balance where the KRW 50 million condition is met.

Since the applicable rate can change as the balance crosses that line, checking the balance bands is worthwhile if you plan to move large sums in and out.

Whether the preferential conditions can actually be met matters too. The preferential rate on 씨드모아통장 is built from marketing consent, first transaction, and a three-month bonus, so the rate rises only by the conditions you meet.

Frequently Asked Questions