Calculate your investment growth with our professional compound interest calculator. Whether you're planning for retirement, saving for college, or building long-term wealth, our calculator provides accurate projections with detailed month-by-month breakdowns.
Plan your 401(k), IRA, and other retirement accounts with accurate compound interest calculations.
Calculate 529 plan growth and other education savings strategies with monthly contributions.
Project long-term investment growth and compare different contribution strategies.
Fill in exactly 4 of the 5 investment variables (initial amount, contribution amount, time period, interest rate, or final value) and leave 1 empty. Our calculator will solve for the missing value and show detailed period-by-period results with CSV export capability.
Compound interest is the interest calculated on the initial principal and the accumulated interest from previous periods. Unlike simple interest, which only calculates interest on the original amount, compound interest allows your money to grow exponentially over time.
When you invest money, you earn returns not just on your initial investment, but also on the returns you've already earned. This creates a snowball effect where your wealth grows at an accelerating rate over time.
Our calculator uses monthly compounding, which means interest is calculated and added to your investment every month. This provides more frequent compounding compared to annual calculations, resulting in higher returns.
A 30-year-old wants to retire at 65 with $1 million. They can invest $500 monthly at 7% annual return. How much will they have?
Parents want to save $100,000 for their child's college in 18 years. They expect a 6.5% annual return. How much should they invest monthly?
Our calculator uses industry-standard compound interest formulas with monthly compounding. The calculations are mathematically accurate for the inputs provided. However, actual investment returns will vary based on market conditions, fees, and other factors not accounted for in the calculation.
Simple interest only calculates returns on your original investment amount. Compound interest calculates returns on both your original investment and all previously earned interest, creating exponential growth over time. This is why compound interest is so powerful for long-term investing.
Our calculator uses monthly compounding, which is more accurate for most investment scenarios. Monthly compounding means interest is calculated and added to your investment every month, providing more frequent compounding compared to annual calculations and resulting in slightly higher returns.
You can account for inflation by using real (inflation-adjusted) returns instead of nominal returns. For example, if you expect 8% annual returns and 3% inflation, use 5% as your interest rate. This gives you the purchasing power of your future investment value in today's dollars.
Historical stock market returns average around 7-10% annually, but this varies by time period and asset allocation. For conservative planning, use 6-7%. For moderate risk, use 7-8%. Remember to consider your actual investment mix and any fees that will reduce your net returns.
Yes! This calculator works for any investment that compounds monthly, including stocks, bonds, mutual funds, ETFs, and savings accounts. Just adjust the interest rate to match your expected returns for each investment type.
Include employer matching in your monthly contribution amount. For example, if you contribute $500 monthly and your employer matches 50% up to 6% of your salary, add the matching amount to your contribution. This gives you the total monthly investment amount.
For planning purposes, use your current contribution amount and then recalculate periodically as your income grows. You can also use the calculator to see how increasing contributions by a certain amount affects your final investment value.
After running a calculation, you'll see an export button that allows you to download your results as a CSV file. This includes the detailed month-by-month breakdown, which is useful for further analysis or record-keeping.
Absolutely! This calculator is excellent for retirement planning. You can calculate how much you need to save monthly to reach your retirement goal, or see how much your current savings will grow by retirement age. It's particularly useful for 401(k) and IRA planning.
Explore our other professional financial calculators to complete your financial planning toolkit.
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Use our investment calculator to plan for long-term wealth building, then use our loan calculators to optimize your debt management strategy. Together, these tools help you make informed financial decisions.