Pay & Living Calculators

Deposit & Savings Interest Calculator

Calculate pre-tax and after-tax interest, maturity payout and the actual yield of time deposits and installment savings.

Calculated in your browser only · inputs are not savedInterest income tax 15.4% · checked October 2026

Enter your values and press Calculate

Maturity payout (after tax)

Principal

Pre-tax interest

Interest tax

View monthly table

How to use

How to use the deposit & savings interest calculator

Choose a product
Choose a time deposit if you place a lump sum at once, or installment savings if you pay in monthly.
Enter the rate and period
Enter the annual interest rate (pre-tax) quoted by the bank and the term in months. The product description states whether it is simple or monthly compounding.
Choose the tax treatment
Most deposits and savings accounts are taxed at the standard 15.4%. For tax-exempt products or mutual finance deposits, choose the matching option.

How it works

With a time deposit, the entire amount earns interest from start to finish. With installment savings, only the money paid in the first month earns interest for the whole term, while the money paid in the last month earns just one month of interest. So even at the same 3% a year, the interest you actually receive from savings is only a little over half of what the same amount would earn in a one-year deposit.

Deposit simple interest = principal × annual rate × months/12 | Deposit monthly compound interest = principal × ((1 + annual rate/12)^months − 1) Savings simple interest = monthly payment × n(n+1)/2 × annual rate/12 | Savings monthly compound interest = monthly payment × Σ((1 + annual rate/12)^k − 1), k = 1…n

After-tax interest is pre-tax interest minus interest income tax. Banks round down to the won in different ways, so the actual amount may differ by a few won.

Basis applied

The withholding rate for interest income tax is 15.4%, combining 14% income tax and 1.4% local income tax. Tax-preferential comprehensive savings (9.5%) were abolished at the end of 2014 and can no longer be opened. For mutual finance deposits at agricultural and fisheries cooperatives, credit unions, Saemaul Geumgo and similar institutions, interest income tax is waived up to KRW 30 million per member or associate member, and only the 1.4% Special Tax for Rural Development is paid. However, from 2026, associate members and members with total salary above KRW 70 million (comprehensive income above KRW 60 million) are taxed separately at 5% in 2026 and 9% from 2027. In that case, enter the applicable rate under 'Enter manually'. (Basis: checked October 2026; sources: NTS withholding tax rates and press reports on the amendment of the Restriction of Special Taxation Act)

FAQ

Why is installment savings interest lower than I expected?

Because each month's payment earns interest for a different length of time. In a 12-month savings plan, the first payment earns 12 months of interest and the last payment earns only 1 month. So the actual interest on a 3% a year savings plan is about 1.6% of total payments.

How different are simple interest and monthly compounding?

On a one-year product the difference is small. Deposit KRW 10 million at 3% a year for one year and simple interest gives KRW 300,000 while monthly compounding gives about KRW 304,000. The longer the term, the bigger the gap from monthly compounding.

Can I still get the 9.5% tax-preferential rate?

Tax-preferential comprehensive savings were abolished at the end of 2014 and can no longer be opened. Deposits and savings with tax benefits today include tax-exempt comprehensive savings (age 65 or over, people with disabilities, etc.), mutual finance deposits and ISA accounts.

When is tax on interest withheld?

Usually the bank withholds 15.4% at maturity or on the interest payment date and pays out the rest. If financial income from interest and dividends combined exceeds KRW 20 million a year, you may need to file a comprehensive income tax return in May of the following year.

What happens if I cancel early?

If you cancel early, the bank's early-termination rate applies instead of the agreed rate, and interest drops sharply. This calculator only covers holding to maturity.

Results are estimates based on your inputs and simplified assumptions, and are for reference only, not a basis for investment decisions.