What Is Compound Interest? How Your Money Can Grow Over Time

After 20 years:

≈ $46,610

After 30 years:

≈ $100,627

Your original $10,000 investment can grow into more than $100,000 simply because the returns continue generating additional returns.

This is why many financial experts encourage people to start investing as early as possible.

Why Compound Interest Matters for Investors

Compound interest is a foundation of long-term investing.

Many popular investment strategies rely on compounding, including:

Stock Market Investing

Investors who buy stocks of strong companies may benefit from:

• share price growth
• dividend payments
• dividend reinvestment

When dividends are reinvested, investors can create another layer of compounding.

Retirement Planning

Retirement accounts often rely on decades of compound growth.

Someone who invests consistently for 30–40 years may accumulate significantly more wealth compared to someone who starts later.

Building Passive Income

Compound growth allows investors to build assets that can eventually generate income without constantly exchanging time for money.

Examples include:

• dividend stocks
• index funds
• bonds
• investment portfolios

The Rule of 72: A Simple Way to Understand Compounding

The Rule of 72 is a quick method to estimate how long it takes for an investment to double.

Formula:

72 ÷ annual return rate = years to double