Compound Interest Calculator

Calculate how your investments can grow over time with the power of compounding.

Investment Details

1,00,000
7.0 %
10 Years

Future Value

0

Total Interest Earned

0

Principal Amount

0

Year-wise Growth Breakdown

Year Starting Balance Interest Earned Ending Balance
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How to Use the Compound Interest Calculator

Project your investment growth with precision — all calculations run locally in your browser for complete data privacy and instant results.

1

Enter Initial Investment

Input your starting principal amount — the initial sum you're investing or saving. The calculator accepts any positive number with up to two decimal places.

2

Set Interest & Time Parameters

Define your annual interest rate (APY), investment time horizon in years, and choose the compounding frequency — from daily to annually.

3

Add Monthly Contributions (Optional)

Include regular monthly deposits to see how consistent savings amplify your returns. You can adjust contribution amounts at any time.

4

Visualize & Download Results

View your projected balance in an interactive chart, see the year-by-year breakdown, and export the data as a CSV file for further analysis.

🔒 100% Client-Side Privacy

Your financial data stays on your device. All compound interest calculations run entirely in your browser — zero server requests, zero logs, zero data storage. Your investment plans remain completely confidential.

Advanced Financial Planning Features

Multiple Compounding Frequencies

Choose from daily, monthly, quarterly, semi-annually, or annually — see how compounding frequency dramatically impacts your long-term growth.

Interactive Growth Visualization

Dynamic charts show your balance evolution over time. The visual breakdown highlights contributions vs. earned interest for clear investment tracking.

Year-by-Year Amortization Table

View a detailed annual breakdown showing starting balance, interest earned, contributions, and ending balance for every year of your investment.

CSV Export & Data Portability

Download your full investment projection as a CSV file. Perfect for importing into spreadsheets, financial software, or sharing with advisors.

Goal-Based Projection & What-If Analysis

Adjust any parameter in real-time to explore different scenarios. See how changing your contribution rate, interest rate, or time horizon affects your final balance instantly.

Frequently Asked Questions

1 What is the formula used for compound interest calculations?
We use the standard compound interest formula: A = P(1 + r/n)^(nt), where A is the final amount, P is the principal, r is the annual interest rate, n is the number of compounding periods per year, and t is the time in years. Monthly contributions are added using the future value of a series formula.
2 How accurate are the projections?
The calculations are mathematically precise using the formula above. However, actual investment returns may vary due to market conditions, fees, and other factors. We recommend using this as a planning tool and consulting with a financial advisor for personalized advice.
3 Can I calculate for both savings and loan scenarios?
Yes. While designed primarily for investment growth, you can use a negative principal or contributions to model loan scenarios. The calculator works for any compounding scenario — savings, mortgages, retirement planning, or debt repayment.
4 Is my financial data secure or stored anywhere?
Absolutely not. All calculations run entirely in your browser's JavaScript engine. No data is ever transmitted to any server, stored in cookies, or saved locally. Once you close the page, all information is permanently erased from memory.
5 What if I want to change my monthly contribution amount over time?
Currently, we use a fixed monthly contribution for simplicity. For varying contributions, you can run multiple scenarios with different average amounts, or export the data to a spreadsheet for more detailed modeling. We're working on adding variable contribution features in future updates.