Deposit/Savings Interest Calculator
Calculates the pre‑tax interest and expected amount at maturity for a lump sum savings account, monthly deposit, input interest rate, tax rate.
Input
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Result
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Monthly payment is calculated on the first day of each month using a linear scenario where monthly interest is computed as annual interest ÷12 without reinvesting interest. The base tax rate is 15.4% and can be input. It is an estimated value based on product payment dates, days, interest payments, discounts, tax exemptions, and financial unit handling. It is not a product recommendation or fixed maturity amount.
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Calculation·conversion criteria
Calculates the pre‑tax interest and expected amount at maturity for a lump sum savings account, monthly deposit, input interest rate, tax rate, and user‑specified rate.
Input example
Every month 100,000 won · 3.5% per year · 12 months · tax rate 15.4% → pre-tax interest 22,750 won · estimated tax 3,504 won · expected final amount 1,219,246 won
A fixed deposit of 100,000 won per month for 12 months at 3.5% per year assumes that the first payment applies a 12-month interest rate and the last payment applies a 1-month interest rate, resulting in a pre-tax interest of 22,750 won. Applying a base tax rate of 15.4% gives a tax of 3,504 won and an expected after-tax final amount of 1,219,246 won.
How to use
- Use the provided example value or replace the calculation type, deposit or monthly payment (won), annual interest rate (%), period (months), and tax rate assumption (%) fields.
- Click Verify result and check the following result.
- Result can be copied if needed.
Frequently Asked Questions
How was the 15.4% tax rate determined?
The default value is a reference amount equal to the general income tax withholding of 14% and 10% of the income tax withholding, i.e., personal local income tax. Since tax exemption, tax incentives, specific products, and individual tax results are not determined, enter the required tax rate directly.
Is it the maturity interest received from the bank?
No. It is calculated on a monthly basis. It may differ due to actual payment dates, maturity dates, number of days, interest payments, reinvestment methods, preferential rates, tax exemptions, and unit handling by each financial company.
Is savings deposited every month?
Assumes initial contributions at the beginning of the month. The first contribution is calculated based on the total number of months, and the last contribution is calculated based on 1 month with linear interest. The actual maturity amount based on the actual date is confirmed in the product manual.
What differs it from a compound interest calculator?
Here, the accrued interest is not added to the principal next month. Use a compound calculator to assume capital growth through reinvestment of interest and monthly payments.
Calculation criteria and reference materials
- Consumer Financial Protection Bureau — Compound and interest calculation cycles
A compound interest calculation assumes no compounding interest; instead, it uses a simple model. A savings calculator distinguishes this by not assuming compound interest.
- National Tax Service — income tax rate for interest income
General income tax withheld: 14%. The rate is a reference to the default value and does not determine tax exemption·reduction·composite taxation for products.
- Korean Law Information Center — Local Tax Act, Article 103-13
A provision stating that 10% of the income tax amount is collected as special local income tax. Refer to the composition of local income tax at 15.4% as a baseline assumption.
Verification of calculation criteria: · Calculation·verification principles · Report errors