Deposit and installment structures
A term deposit keeps the initial principal invested for the agreed period. Under simple interest, the core relationship is principal × annual rate × term.
With installment savings, the first payment earns interest the longest and the last payment the shortest. Applying the annual rate to every contribution for the full term would overstate interest.
- Deposit: one principal with one investment period
- Installment savings: a different period for every payment
- Bonus rate: confirm whether you meet every condition
Before-tax and after-tax amounts
Before-tax interest is the amount before withholding. After-tax interest subtracts the tax rate entered by the user.
Tax-free or preferential treatment depends on the product and account holder. Match the calculator's tax setting to the product terms; Baro Tool does not determine tax eligibility.
Example: 500,000 won monthly for 12 months
Twelve payments produce 6 million won in principal. Even at 4% simple interest, the interest is below 240,000 won because the full 6 million is not invested for the entire year.
Payment timing, exact day counts, and bank rounding can create a small difference from the final maturity amount.
- Principal = monthly payment × number of payments
- After-tax interest = before-tax interest × (1 - tax rate)
- Maturity amount = principal + after-tax interest
Compare products on the same basis
Use the same payment, date, term, and tax rate. A high maximum rate may require salary deposits, card spending, or other conditions that lower the rate if unmet.
Early-withdrawal and post-maturity rates differ from the headline rate. Review those rules if you may not keep the product to maturity.