Accurately calculate interest on savings and deposits to help with financial planning. Choose between simple and compound interest methods, and automatically calculate after-tax amounts.
Final Amount
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Principal
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Interest (Pre-tax)
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Interest Income Tax (15.4%)
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Interest (After-tax)
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β» Based on 2025 interest income tax rate of 15.4% (income tax 14% + local tax 1.4%) β» Tax-exempt products or tax-advantaged products require separate calculation. β» Actual amounts may vary depending on financial institution terms.
This calculator applies South Korean tax law (as of 2025).
GUIDE
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01
Korean Savings & Deposit Market and Rate Trends
As of 2025, the Korean deposit and savings market remains competitive despite a low-rate environment. The 2024 average fixed-deposit rate was about 3.5% and installment savings about 3.7%. Commercial banks offer 3.0-3.5%, while regional banks and savings banks offer 0.3-1.0pp higher. Internet-only banks (KakaoBank, TossBank, K-Bank) offer 0.5-0.8pp higher thanks to lower operating costs. Savings banks offer higher rates (4.5-5.5%) within the deposit-protection limit (50M KRW). Interest income tax is 15.4% (14% income tax + 1.4% local tax); tax-exempt or tax-advantaged products can reduce taxes.
02
Difference Between Deposit and Installment Savings
A fixed deposit places a lump sum and returns principal plus interest at maturity. Installment savings deposit a fixed amount monthly. A deposit earns interest on the full principal, while installment savings earn graduated interest on each monthly contribution, so at the same rate a deposit earns more. Saving 12M KRW for a year at 3.5% yields roughly 420K KRW for a deposit versus 230K KRW for installment savings. Deposits suit those with a lump sum; installment savings suit building a monthly saving habit.
03
Simple vs Compound Interest
Simple interest is calculated only on the principal and is how most deposits and savings operate. Compound interest adds interest on interest, growing larger over longer periods. Depositing 10M KRW at 4% simple interest for 5 years yields 2M KRW interest, while compound yields about 2.16M KRW. Over 10+ years, compound can be 30-50% larger than simple. In practice, equity funds or ETFs are better suited to long-term compounding than deposits.
04
Comparing Rates Across Institutions
As of 2025, commercial banks offer base 1-year deposit rates of 3.0-3.5%, with preferential conditions (salary transfer, card use, auto-transfer) adding 0.5-1.0pp. When choosing, compare nationwide rates on the FSS comparison site (finlife.fss.or.kr), confirm preferential conditions are achievable, consider early-termination penalties, and diversify within the deposit-protection limit (50M KRW).
05
Interest Income Tax and Tax-Advantaged Products
Deposit/savings interest is automatically withheld at 15.4% (14% income tax + 1.4% local tax). Depositing 10M KRW at 4% for a year earns 400K KRW interest, but only 338.4K KRW after 61.6K KRW tax. Long-term housing savings exempt interest tax after 7+ years for those without a home; the Noranusan mutual-aid offers income deduction and tax exemption; cooperative deposits get a 1.4% low rate up to 30M KRW; and tax-advantaged comprehensive savings tax interest at only 9.5% up to 100M KRW per person.
06
Designing Savings Maturity and Building a Nest Egg
Installment savings need a clear goal and period. To reach 30M KRW in 3 years at 3.5%, deposit about 800K KRW monthly. Saving 20-30% of income is recommended. Strategies: set auto-transfers for a "save first, spend later" habit, run multiple savings to stagger maturities, choose long-term savings when rates are high and short-term when low, and place bonuses in separate lump-sum deposits.
07
Early Termination and Post-Maturity Management
Terminating early applies an early-termination rate of just 50-70% of the agreed rate, causing losses. To avoid this, set an amount and period you can maintain to maturity, keep a separate emergency fund, and use products with partial-withdrawal features. After maturity, undrawn balances earn a low post-maturity rate (usually 1-2%), so sign up for a one-month maturity alert and immediately re-enroll in a higher-rate product.
08
Deposit Protection and Choosing Safe Institutions
The deposit protection scheme protects up to 50M KRW (principal plus interest) per person per institution if a bank fails. Amounts above 50M KRW are unprotected, so large funds should be spread across institutions. Criteria for a safe institution include a high BIS capital ratio (8%+ normal, 10%+ excellent), high credit rating (AA+), and preferring large commercial / first-tier banks.
09
Special Deposits and Event Products
Institutions periodically launch special deposits offering 0.5-1.5pp above market rates. The 2024 average special-deposit rate was 4.5% versus 3.2% for regular deposits. Strategies: regularly check bank sites and finance communities, sign up quickly since limited quantities sell out, confirm conditions in advance, and compare special offers across banks for the best rate.
10
Using the Calculator and Optimizing Financial Planning
A savings/deposit interest calculator automates complex interest math to predict the exact maturity amount. Depositing 1M KRW monthly for 24 months at 3.5% simple yields 24M principal, about 730K pre-tax interest, about 620K after-tax, for roughly 24.62M total. Strategies: compare yields across products, back-calculate from a target amount, compare simple vs compound, and plan based on after-tax amounts.