Compound Interest Calculator for Future Value

Monthly-compounded growth with contributions

Use this compound interest calculator to estimate how much an investment could grow over time with monthly contributions, taxes, fees, and inflation. Compare ideal vs net future value, then use charts and yearly tables to test savings growth and long-term investing scenarios.

Future Value (FV)

How compounding grows your assets

Monthly basis

Verified monthly compounding with end-of-month deposits

Tax & Fee

See net results after costs

Inputs

Basic Inputs

Initial Principal (×10k KRW)Monthly Contribution (×10k KRW)Annual Rate (%)Years

Verified samples

A-D are KRW-based samples used by the verification script. Clicking a preset switches the currency to KRW and fills amounts in 10k KRW units.

Cost & Inflation OptionsApply tax ON · Apply fees ON

Apply taxWhen tax is off, the entered rate is preserved but excluded from the calculation.Tax rate (%)

Apply feesWhen fees are off, the entered annual fee rate is preserved but excluded from the calculation.Yearly fee (%)

Inflation rate (%)

Advanced

Calculation basis

Monthly compounding

The verified compound calculation is fixed to monthly compounding. Annual-compounding comparison is reserved for a later verified update.

Currency

Quick starting examples

$10,000 principal · $300/month · 5% · 10 years
$500/month · 7% · 20 years
$50,000 principal · 4% · 15 years

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FAQ

What does this compound interest calculator do?

It calculates future value (FV) using principal, monthly contributions, annual return, and time horizon on a fixed monthly-compounding basis.

Is this calculator monthly or annual compounding?

It uses verified monthly compounding with end-of-month contributions. Annual compounding is explained separately and is not a selectable calculation mode here.

How are monthly contributions calculated?

Each end-of-month contribution compounds for its remaining months and is added to the future value of the initial principal.

What is the difference between net and ideal results?

Ideal results ignore taxes and fees, while net results reflect performance after tax and fee deductions.

How are taxes and fees applied?

The annual fee is deducted from the assumed annual return, and the entered tax rate is applied to positive pretax investment gains at the final point in this simulation.

How is the inflation-adjusted value calculated?

The after-tax final value is discounted by the entered annual inflation rate over the selected time horizon to estimate present value.

Can I use this calculator for ETF investing?

Yes, as a planning scenario based on an assumed average return. Actual ETF returns, distributions, taxes, fees, and currency effects can vary.

Does the result guarantee future investment returns?

No. It is an educational simulation based on fixed assumptions, not a forecast or investment recommendation.