Savings Maturity Calculator
Calculate your installment savings maturity balance and after-tax payout from monthly deposit, rate, and term
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This tool calculates the maturity balance of a monthly installment savings account under both simple and monthly-compound interest, and shows your take-home amount after the 15.4% interest income tax—all at once. When comparing bank products or setting a savings goal, you can quickly see how much actually lands in your hands on an after-tax basis.
How to use
- Choose the simple-interest or monthly-compound method on the tab.
- Enter your monthly deposit, annual rate (%), and term (months).
- Review the principal deposited, pre-tax interest, interest tax (15.4%), and after-tax maturity payout.
- Use 'Copy result' to copy the breakdown for your notes or comparisons.
FAQ
- How do simple and monthly-compound interest differ?
- With simple interest, interest accrues only on the principal you deposit each month; with monthly compounding, interest also accrues on the interest added each month. At the same rate, monthly compounding yields slightly more interest at maturity. This calculator assumes deposits at the start of each month and a lump-sum payout at maturity.
- What is the 15.4% tax?
- It's the tax on interest income—the standard rate combining 14% income tax and 1.4% local income tax. Your actual after-tax interest is the pre-tax interest minus this rate. The rate differs for tax-free or tax-advantaged products.
- Does it exactly match the bank's maturity amount?
- It's an approximation using the standard installment-interest formula, so it may differ and is for reference only. Your actual payout can vary with each bank's interest-calculation dates, preferential-rate conditions, tax-free status, and rounding to the won, so confirm the final amount with the financial institution.