Savings Deposit Interest Calculator

Estimate deposit interest, tax drag, account fees, and after-tax value for savings-style products.

Savings and deposit interest calculator

Calculate Korean term-deposit or installment-savings interest after normal, preferential, or tax-free treatment, including early termination effects.

Maturity amount

₩30,888,300

Net interest

₩888,300

Tax ₩161,700

Effective annual rate

3.0%

Early interest loss

Not selected

Deposit vs installment interest gap

₩407,137

Total principal

₩30,000,000

Uses the Korean savings/deposit engine with 15.4% normal tax, 9.5% preferential tax, tax-free treatment, simple/compound interest, and early-termination multipliers. This English finance calculator calls the same Korean pure calculation module as the Korean page. KRW and Korean statutory thresholds are preserved instead of the old generic percentage stub.

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Savings and deposit interest guide

This English guide translates the Korean savings and deposit interest calculator. The calculator calls calculateSavingsDeposit, calculateEarlyTermination, and compareDepositVsInstallment to preserve the Korean product, tax, and early-termination formulas.

Deposit versus installment savings

A term deposit earns interest on one lump-sum principal. An installment savings product receives monthly payments, so the first payment earns interest for the full term while later payments earn interest for fewer months.

The Korean engine supports simple and compound interest for both product types. It reports total principal, gross interest, tax amount, net interest, maturity amount, effective annual rate, and monthly details.

Tax treatment

Normal Korean interest taxation is 15.4% normal tax, including local income tax. The preferential case uses 9.5% preferential tax, while the tax-free case applies a 0% tax rate inside eligible tax-free savings rules.

The calculator keeps taxationType as an explicit input because two products with the same advertised annual rate can have different net interest after tax. This is especially important for small tax-preferred savings accounts.

Early termination

The early-termination calculation does not simply prorate the maturity interest. It reduces the annual rate using early-termination multipliers, including 0.1, 0.3, 0.5, and 0.7 early-termination multiplier bands depending on elapsed term.

The result compares original maturity interest with early-result interest, then reports interest loss and rate loss. Use this before breaking a deposit or installment product for a higher headline rate elsewhere.