Calculate future value, ROI, and investment returns with compound interest
Our free Investment Calculator helps you project the future value of your investments using compound interest. Whether you're planning for retirement, saving for a major purchase, or evaluating a stock portfolio, this tool gives you a clear picture of how your money can grow over time.
This calculator uses the compound interest formula to project investment growth based on your initial investment, regular monthly contributions, expected annual return rate, and investment time horizon. It supports multiple compounding frequencies — annual, semi-annual, quarterly, monthly, and daily — and generates a year-by-year breakdown of your portfolio's growth.
Compound interest is often called the "eighth wonder of the world" because it allows your returns to generate their own returns over time. The longer your investment horizon, the more dramatic the compounding effect becomes. This calculator makes that effect visible and tangible.
The most powerful lever in long-term investing is time. Starting 10 years earlier can more than double your final portfolio value, even with the same contributions and return rate. Use this calculator to visualize the cost of waiting — it's one of the most motivating things you can do to encourage consistent saving habits.
Be realistic with your return rate assumptions. The S&P 500 has historically returned around 7-10% annually before inflation, but individual years vary wildly. For conservative planning, use 6-7%. For aggressive scenarios, you might model 10-12%. Running multiple scenarios with different rates gives you a range of outcomes to plan around.
Don't underestimate the power of monthly contributions. Even adding $100/month to a $10,000 initial investment at 8% over 30 years adds over $140,000 to your final balance compared to no contributions. Consistency matters more than the size of any single contribution.
This calculator is completely free, requires no login, and works entirely in your browser. The year-by-year breakdown table gives you more insight than a simple final number — you can see exactly when compound interest starts to accelerate and how your interest earned begins to outpace your contributions over time.
The auto-recalculate feature means you can adjust any input and instantly see the impact, making it easy to run "what if" scenarios without clicking a button each time. It's a practical tool for anyone making financial decisions, from first-time investors to experienced portfolio managers.
Your privacy is our priority. All processing happens entirely in your browser using JavaScript. No files, data, or inputs are ever uploaded to any server. Everything stays on your device, making this tool completely safe to use with sensitive content.
A lump sum investment is a single upfront payment. Regular contributions (dollar-cost averaging) means investing a fixed amount at regular intervals. Regular contributions reduce the impact of market timing and are more accessible for most investors. This calculator supports both approaches.
Historical average annual returns: US stock market (S&P 500) ~10% nominal, ~7% inflation-adjusted. Bonds ~3-5%. Savings accounts ~1-5% depending on current rates. Use conservative estimates (6-7%) for long-term planning to avoid overestimating your future wealth.
Inflation erodes purchasing power over time. A 10% nominal return with 3% inflation gives a real return of about 7%. For long-term projections, use the real (inflation-adjusted) return to understand what your money will actually be worth in today's dollars.
Investment fees (expense ratios, management fees) compound over time just like returns — but in reverse. A 1% annual fee on a 7% return effectively reduces your return to 6%. Over 30 years, this can reduce your final portfolio value by 20-25%. Low-cost index funds typically charge 0.03-0.20%.
CAGR (Compound Annual Growth Rate) is the rate at which an investment would have grown if it grew at a steady rate. Average annual return is the arithmetic mean of yearly returns. CAGR is lower but more accurate for measuring actual investment performance over time.