Compound Return Calculator
Enter your initial investment, monthly contribution, and expected return rate to see the compound growth projection and year-by-year breakdown.
Investment Parameters
S&P 500 historical avg ~10%, Korean stock avg ~8% for reference
Your input stays in your browser and is never sent to a server.
Compound Growth Result
Compound return +63.26%
- Total Principal
- 70,000,000KRW
- Total Return
- +44,279,240KRW
- Final Assets
- 114,279,240KRW
The compound effect means returns generate further returns. The longer the period, the more exponentially gains grow relative to principal.
This calculator uses monthly compounding (beginning of period). Actual returns vary by market conditions each year; use for reference only.
Taxes (capital gains tax, dividend tax, etc.) and fees are not reflected in this simple simulation.
How is compound return calculated?
Compound investing means returns generate further returns. By contributing a fixed amount monthly while compound interest accumulates, you can build significantly more wealth than the principal alone over the long term.
Monthly rate r = Annual rate / 12
Initial compound = Initial x (1 + r)^n
Contribution compound (annuity-due) = Monthly x ((1 + r)^n - 1) / r x (1 + r)
Final assets = Initial compound + Contribution compound
Example -- 10M KRW initial + 500K KRW/month at 8% annual for 10 years: total principal 70,000,000 KRW, final assets 114,279,240 KRW, return 44,279,240 KRW (return rate 63.26%).
Frequently Asked Questions
Q. What is the difference between compound and simple interest?
Simple interest accrues only on the principal, while compound interest earns interest on previously earned interest. For example, 1M KRW at 10% compound interest for 10 years becomes about 2.59M KRW, versus only 2M KRW with simple interest. The longer the period, the more dramatic the compound effect.
Q. How should I set the expected annual return?
You can reference historical data. The S&P 500 historical average annual return is about 10% (before inflation), and KOSPI averages around 8%. However, past returns do not guarantee future results, and actual returns vary each year.
Q. Are taxes reflected?
This calculator is a simple simulation that does not include taxes (capital gains tax, dividend tax, etc.) or fees. Actual after-tax returns vary by investment product and how gains are realized.
Q. What is the difference between annuity-due and ordinary annuity?
This calculator uses annuity-due, meaning contributions are made at the beginning of each month. Compared to ordinary annuity (end-of-month contributions), each payment is invested one month earlier, so the result is slightly higher.
This calculator is for reference only. Actual investment returns vary by market conditions each year, and taxes and fees are not included. Do not use as a basis for investment decisions.