Compound Interest Calculator

See how an initial investment and recurring contributions may grow through compounding over time.

All amounts are calculated and displayed in South Korean won (KRW).

Investment settings

Enter the assumptions used to estimate future assets.

Initial investment *

KRW

Recurring contribution *

KRW

Contribution frequency *

Investment period *

years

Annual interest rate *

Compounding frequency *

Contribution timing

End of periodBeginning of period

Optional settings: inflation and simplified tax

Blank values are not applied. These inputs do not predict inflation or tax law.

Annual inflation rate

Simplified tax rate on gains

Estimated results

Estimated assets: ₩0
Total contributed principal: ₩0
Estimated net gain: ₩0

Asset growth chart

Estimated assetsContributed principalInterest

Enter values and calculate to display the asset growth chart.

View details

After calculation, this table shows yearly principal, interest, and projected balances.

How the calculation works

The initial investment earns interest at the selected compounding frequency. Recurring contributions are added monthly or yearly at the selected timing.

Future value = compounded initial investment + compounded recurring contributions

The optional simplified tax is applied once to positive interest at the end of the period. The inflation option discounts the after-tax balance to an estimated present value.

Before you calculate

The investment period accepts whole years from 1 to 100.
The rate and contribution amount are assumed to stay unchanged for the full period.
Fees, withdrawals, market volatility, and product-specific tax rules are not included.
The estimated asset multiple compares projected assets with contributed principal; it is not a rate of return.

Frequently asked questions

What is compound interest?

Compound interest earns interest on both principal and previously accumulated interest. Over longer periods, its result can differ substantially from simple interest at the same rate.

How do monthly and yearly contributions differ?

Monthly contributions are added every month, while yearly contributions are added once a year. Different timing and frequency can produce different projected balances.

What is the difference between beginning and end contributions?

A beginning-of-period contribution receives one more compounding period than an end-of-period contribution. With positive rates and contributions, beginning contributions produce a higher projected balance.

How does compounding frequency affect the result?

At the same nominal annual rate, more frequent compounding generally produces a higher projected balance. This calculator supports annual, semiannual, quarterly, monthly, and daily compounding.

How are tax and inflation applied?

The simplified tax rate is applied once to positive interest at the end of the selected period. The after-tax balance is then discounted by the inflation rate. Actual tax rules and financial products may differ.

Why can actual results differ?

Rates, contribution timing, fees, tax law, inflation, and market conditions can change. This calculator is a fixed-input scenario, not a forecast or guarantee.

Related calculators

Other financial calculators are available in Korean while their localized versions are prepared.