After-Tax Interest Calculator - Net Interest After Tax

Calculator/Finance Calculator/ After-Tax Interest Calculator

What is after-tax interest?

Interest from deposits and savings is subject to a 15.4% interest income tax. This calculator shows the interest you actually receive after tax and the maturity amount.

Enter Your Details

Product Type

Interest Method

Principal

The lump sum you deposit at once.

Annual Interest Rate

The annual interest rate. e.g., 3.5

Term

months

Enter the term in months. e.g., 12

Tax Type

How It Is Calculated

First the pre-tax interest is calculated, then the interest income tax (15.4% standard) is deducted to get the after-tax interest. For deposits, interest applies to the whole lump sum; for installment savings, each monthly deposit earns interest for the remaining term.

How to Use

Select the product type: deposit or installment savings.
Enter the principal (or monthly deposit), annual rate, and term.
Select the tax type (standard, preferential, or tax-free).
Press Calculate to see your after-tax interest and maturity amount.

Example

For example, depositing 10 million KRW at 3.5% simple interest for 12 months gives 350,000 KRW pre-tax interest; after deducting the 15.4% tax (about 53,900 KRW), the after-tax interest is about 296,100 KRW.

Frequently Asked Questions

How much is the interest income tax?

Generally, 15.4% (income tax 14% + local income tax 1.4%) is levied on interest.

What are tax-free and preferential taxation?

Tax-free means no tax on interest, while preferential taxation applies a lower rate of 9.5%. Eligibility conditions vary by product.

How do simple and compound interest differ?

Simple interest applies only to the principal, while compound interest earns interest on interest, making the maturity amount larger.