Korea Savings Interest Calculator — After-Tax Interest on Deposits
Last verified: 13 September 2026 · Figures follow Korean law and official rates; confirm the current rate at the linked source.
Korean banks quote interest rates before tax and withhold the tax when they pay the interest. The calculator above shows what you actually get at maturity from a lump-sum time deposit (jeonggi yegeum, 정기예금) or monthly installment savings (jeokgeum, 적금). It opens with example figures, so replace them with your own.
How it’s calculated
- Deposit, simple interest: principal × annual rate × days ÷ 365. The calculator counts each month as 365/12 days.
- Deposit, compounded yearly: principal × ((1 + annual rate)years − 1).
- Installment savings: monthly payment × annual rate × n × (n + 1) ÷ 2 ÷ 12, where n is the number of months. Each payment earns interest only for the months it sits in the account.
The bank then withholds tax on the interest: 15.4% at the standard rate, made up of 14% national income tax and 1.4% local income tax. Your payout is the principal plus the interest left after tax.
Who this applies to
The 15.4% standard rate is for Korean tax residents. Under the Income Tax Act you are generally a resident if you have a domicile in Korea or have lived here for 183 days or more, whatever your nationality. Our guide to income tax for foreign workers explains the test.
If you are a non-resident, different withholding rules apply, and a tax treaty between Korea and your home country may change the rate. Ask your bank which rate it withholds before relying on the result. Choose the 9.5% or tax-free options only if your bank confirms the account qualifies. And if your interest and dividends together pass ₩20 million in a year, the excess is taxed with your other income at progressive rates, so your final tax can be higher than 15.4%.
Worked example
The default inputs are a ₩10,000,000 deposit at 3.5% for 12 months, simple interest, standard tax. Interest before tax is ₩350,000, the bank withholds ₩53,900, and you keep ₩296,100. The payout at maturity is ₩10,296,100 (about 10.3 million won), an effective yield of 2.96% a year after tax.
Switch to installment savings and the default becomes ₩500,000 a month at the same rate and term:
| Time deposit | Installment savings | |
|---|---|---|
| Paid in | ₩10,000,000 on day one | ₩500,000 a month (₩6,000,000) |
| Interest before tax | ₩350,000 | ₩113,750 |
| Tax withheld (15.4%) | ₩53,900 | ₩17,518 |
| Interest after tax | ₩296,100 | ₩96,233 |
| Payout | ₩10,296,100 | ₩6,096,233 |
Figures are rounded to the won, as in the calculator. On average each installment payment sits in the account for 6.5 of the 12 months, which is why the savings account earns a little over half as much interest per won.
Where to check
- National Tax Service (English site): Korea’s tax authority. Check the rules for interest income and for non-residents here or with your bank.
- Bank of Korea: the base rate, which bank deposit rates follow.
Frequently asked questions
How much tax do I pay on bank interest in Korea?
Tax residents pay 15.4%: 14% national income tax plus 1.4% local income tax. The bank withholds it when it pays the interest, so the amount credited to your account is already after tax.
Why does installment savings pay less interest than a deposit at the same rate?
Each monthly payment earns interest only from the month it goes in. Over 12 months, ₩500,000 a month at 3.5% earns ₩113,750 before tax, while ₩6,000,000 deposited on day one would earn ₩210,000.
Do non-residents pay the same 15.4%?
Not necessarily. Non-residents are taxed under different rules, and a tax treaty between Korea and their home country may change the rate. Ask your bank which rate it withholds before relying on the calculator’s result.