Compound Interest Calculatorcompound Interest Calculator

🚀 Compound Interest Calculator

A simple yet powerful web-based compound interest calculator that helps you understand how your investments grow over time. This calculator takes into account both the initial principal and monthly investments, providing a detailed breakdown by year to show the growth of your investments.

🚀 Quick Start

1. Enter your initial investment amount in the "Initial Principal" field.
2. Input your planned monthly contribution.
3. Set the expected annual interest rate (in percentage).
4. Click "Calculate Earnings" to view the prediction of your investment growth.

✨ Features

• Compound interest calculation with monthly contributions.
• 30-year investment prediction.
• Monthly interest calculation frequency.
• Detailed breakdown including:
  • Principal amount.
  • Interest earned.
  • Total balance.
• User-friendly interface.
• Responsive design.
• Real-time calculation.

💻 Usage Examples

If you start with the following amounts:

• Initial principal: $1,000
• Monthly investment: $100
• Annual interest rate: 7%

The calculator will display:

• Year-by-year growth.
• Total investment principal.
• Annual interest income.
• Running balance.

🔧 Technical Details

This calculator is built using the following technologies:

• HTML5
• CSS3
• Pure JavaScript
• Responsive design principles

📚 Documentation

Calculation Method

The calculator uses the following methods:

• Monthly interest calculation.
• Adding monthly contributions after applying interest.
• Displaying an annual summary including:
  • Total investment principal (initial + monthly contributions).
  • Interest earned during the year.
  • Total balance at the end of the year.

Usage Instructions

• All currency inputs are in US dollars ($).
• Interest rates should be entered as a percentage (e.g., 7 means 7%).
• Results are shown for a 30-year period.
• Calculations assume monthly interest accrual.