Installment savings interest
Calculate pre-tax interest, after-tax interest, and maturity amount from monthly deposit, term, annual rate, and tax rate.
When to use this calculator
Estimate principal, gross interest, tax, net interest, and maturity value for regular monthly savings deposits.
- Comparing monthly savings products
- Estimating the effect of term and rate
- Planning a target maturity amount
Worked examples
Twelve-month savings
KRW 300,000 per month for 12 months at 4% with 15.4% tax produces an estimated maturity near KRW 3.666 million.
Deposit timing
Earlier monthly deposits earn interest for longer than later deposits.
Frequently asked questions
Why is interest lower than principal × rate?
Each monthly deposit earns interest for a different number of months.
Is 15.4% always the tax rate?
It is a common Korean general-tax assumption, but tax-advantaged products differ.
Are preferential rates included?
Only the annual rate entered is used.
How to interpret the result
Banks can use day-count conventions and rounding rules that produce slightly different figures.
Confirm product conditions, early-termination rates, and tax benefits with the financial institution.