Investment Calculator

Project your investment growth with compound interest. Free online investment calculator for long-term planning.

What is Investment Calculator?

An investment calculator helps you project how your money will grow over time through the power of compound interest. Whether you're planning for retirement, saving for a major purchase, or building wealth for the future, this calculator shows you the potential growth of your investments based on your initial contribution, regular additions, expected rate of return, and time horizon.

Compound interest is often called the most powerful force in finance because it allows your money to earn returns on both your original investment and the returns you've already accumulated. Over long periods, this compounding effect can turn modest regular contributions into substantial wealth. Starting early is the single most important factor in investment success.

Formula

Future Value = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) - 1) / (r/n)]

Where: P = Initial investment, PMT = Regular contribution, r = Annual return rate, n = Compounding frequency, t = Time in years

How to Calculate

Enter your initial investment amount.
Input your regular monthly or annual contribution.
Specify the expected annual rate of return.
Set the investment time horizon in years.
View the projected future value, total contributions, and total earnings.

Example

Starting with $5,000 and contributing $200 monthly for 30 years at an 8% annual return: Total contributions = $5,000 + ($200 × 360) = $77,000. Future value = approximately $291,000. Total earnings = $214,000. Your money grew nearly 4x through compound interest, with earnings exceeding contributions by almost 3 to 1.

Key Benefits

Project growth over decades with compounding
See regular contribution dollar-cost averaging
Adjust rate and horizon for optimal strategy
Compare taxable vs tax-advantaged growth

Common Mistakes to Avoid

Market timing instead of long-term investing
Emotional buying high selling low
Not diversifying across asset classes

Pro Tips

Start early for most powerful compounding
Keep costs under 0.1 percent expense ratio
Rebalance portfolio annually

Key Terms Explained

Compound Growth: Earnings on earnings
Dollar-Cost Averaging: Fixed regular investing
Asset Allocation: Split across asset classes
Expense Ratio: Annual fund fee percentage

When to Use This Calculator

Starting new portfolio for growth projection
Setting monthly contribution goals
Comparing account type strategies

Common Use Cases

Planning retirement savings and estimating future nest egg
Setting college savings goals for children
Comparing different investment strategies and contribution levels
Understanding the impact of starting to invest early vs. late

Frequently Asked Questions

What rate of return should I use?

Historically, the stock market (S&P 500) has averaged about 10% annually before inflation, or 7% after inflation. Conservative investments like bonds typically yield 3-5%. Use realistic estimates based on your investment mix.

How does starting early affect my investments?

Starting early has a massive impact due to compounding. Someone who invests $200/month from age 25 to 35 (10 years) and then stops will likely have more at 65 than someone who starts at 35 and invests $200/month for 30 years.

Should I focus on the initial amount or regular contributions?

Regular contributions matter more for most people. Consistent monthly investing, even in small amounts, builds wealth over time through dollar-cost averaging and compound growth.

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