What is the difference between simple interest and monthly compound interest?

Simple interest is calculated on principal only, while monthly compound interest adds monthly interest to principal before calculating the next month.

It represents Korea's common interest-income tax rate (14% income tax + 1.4% local tax).

Can I simulate tax-exempt products?

Yes. Select tax-exempt mode (0%) to compare after-tax outcomes.

Will the result exactly match my bank's maturity amount?

This is an estimate assuming a fixed displayed annual rate and interest paid at maturity. Day-count rules, payment frequency, rounding, promotional-rate requirements, and product-specific tax rules can change the actual amount.

TOOLOG / WEB UTILITY

Savings Interest Calculator | Simple or Monthly Compound Returns

Enter a deposit, annual rate, term, and tax mode to estimate pre-tax interest, tax, after-tax interest, and maturity amount with simple or monthly compounding.

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Deposit amount

Annual interest rate (%)

Term (months)

Interest method

Tax mode

Estimate assumes the displayed annual rate stays fixed, interest is paid at maturity, and tax is applied once to total interest. Actual bank rounding and product rules may differ.

-Pre-tax interest

-Tax amount

-After-tax interest

-Maturity amount

Enter deposit, rate, and term to estimate maturity amount.

When is this savings interest calculator useful?

When comparing fixed deposits, savings accounts, parking accounts, or short-term deposits, the headline rate alone does not show how much interest you will actually keep after tax. Enter the deposit amount, annual interest rate, term, and tax treatment to estimate both pre-tax interest and the after-tax maturity amount.

Key features

Choose simple interest or monthly compound interest
Compare 15.4% Korean interest-income tax or 0% tax-exempt treatment
See pre-tax interest, tax, after-tax interest, and maturity amount together
Use quick 6-, 12-, or 24-month term presets and a sample input
Copy the result for a deposit comparison sheet

How to use it

Enter the deposit amount, annual interest rate, and deposit term in months.
Select simple interest or monthly compounding.
Choose the tax mode: 15.4% taxable or 0% tax-exempt.
Review the pre-tax and after-tax results, then copy them if needed for comparing products.

Calculation assumptions

Simple interest uses deposit × annual rate × months ÷ 12.
Monthly compound mode assumes the annual rate divided by 12 is credited to principal every month.
Tax is applied once to the estimated total interest.
Actual bank results may differ because of day-count conventions, interest payment schedules, promotional-rate requirements, rounding, and product-specific tax rules. Confirm the final amount in the product disclosure.