Investment Calculators

Free investment calculators to plan your financial future

Investing works best when you can actually see where you're heading. Our investment calculators turn abstract percentages into concrete numbers, so you can picture how your money might grow over years and decades. They're free, need no sign-up, and are built to be genuinely useful for everyday investors rather than professionals.

Project your portfolio and savings growth

The stock investment calculator lets you build a portfolio of major US stocks and ETFs, set an expected growth rate for each, and project how your investment could develop over time with clear charts. The compound interest calculator shows the quiet power of compounding — how regular contributions and reinvested growth build wealth year after year.

Plan with realistic expectations

Every projection is only as good as its assumptions, which is why these tools let you adjust growth rates, contributions and time horizons to explore different scenarios. Real markets rise and fall, and no calculator can predict the future — but seeing the range of possible outcomes helps you set realistic goals and understand the long-term impact of investing consistently.

Compound interest and stock growth are not the same thing

Both are usually described as “growth at x percent a year”, which hides a real difference. Compound interest describes a known rate applied to a balance that keeps getting larger — a savings account, a GIC or CD, a bond held to maturity. The rate is agreed in advance, the path is smooth, and you can work out the ending balance on day one. That is exactly the situation the compound interest calculator models, and for that situation it is precise.

Stock market growth is a different animal wearing the same coat. When you read that the broad US market has returned about 10 percent a year before inflation over the long run, that figure is an average pulled from decades of years that looked nothing like each other — some up thirty percent, some down thirty. Almost no individual year actually lands on the average. The average is a summary of a rough ride, not a description of it.

Why a single flat rate flatters the picture

Assuming a steady annual percentage does more than simplify — it quietly improves the answer. A holding that falls 50 percent needs to double just to get back to where it started, so losses cost more ground than the same-sized gains recover. Two portfolios that share an identical average annual return can therefore finish at different values, with the bumpier one ending lower. The smoother the assumed path, the better the projection looks compared with what a real, volatile version of the same average would have produced.

This is why the stock investment calculator doesn't treat every holding as a straight line. It draws on each stock's real historical returns and real historical volatility, converting that volatility into a plain 1–7 risk rating so you can see at a glance which holdings have had a calm history and which have swung hard. It also accounts for dividends and for contributing steadily over time rather than all at once. None of that is a forecast — it is history, described honestly, so your assumptions start from something real.

Risk and return, without the jargon

In investing, “risk” is less about the chance of disaster and more about the width of the range of outcomes. A holding with a narrow range is predictable; a holding with a wide range may end up far above or far below its average, and you don't get to choose which. Historically, the assets with the higher long-run returns have been the ones with the wider ranges — cash and guaranteed products barely move but have struggled to outpace inflation, a broad market index swings considerably more while averaging more, and an individual company is wider still, because everything specific to that one business lands on you.

Spreading money across many holdings dilutes the company-specific part of that risk: one firm's bad quarter matters less when it is a small slice. What diversification cannot remove is market-wide risk — in a broad downturn, most things fall together, which is exactly when investors are most tempted to sell.

Time horizon changes the whole question

The most important input in any of these projections isn't the growth rate — it's how long the money stays invested. Money you need within a couple of years has no room to recover from a bad stretch, so volatility is a genuine threat to the plan rather than a temporary annoyance. Money that can sit for twenty or thirty years is in a different position: long horizons have historically smoothed out individual bad years, and steady contributions during downturns buy more shares at lower prices.

Long horizons also expose the risk people forget. Inflation at three percent roughly halves the purchasing power of cash in about twenty-four years, so “safe” money sitting still is losing quietly rather than not moving at all. This is why it's worth distinguishing nominal returns from real ones — the same long-run market average of around 10 percent before inflation is closer to 6 or 7 percent after it, and the second number is the one that tells you what your future money will actually buy.