An investment return calculator answers a simple question: if my money earns a certain rate each year, what does it become? The default models a $10,000 lump sum at 8% a year for 10 years, with no extra contributions, so you can see pure compounding at work.
It also separates two numbers people often confuse — the nominal rate you’re quoted, and the effective annual rate (APY) you actually earn once compounding is counted.
How to read your investment return
Total return is just your ending balance minus what you put in. The calculator splits your final total into contributions versus interest, so you can see how much of your result is money you deposited and how much the market produced. For a lump sum left alone, every dollar above your principal is pure return.
The growth curve shows the path, not just the destination — useful because returns compound, so the dollar gains get larger each year even when the percentage rate stays the same.
Nominal vs effective (APY) return
A rate quoted as “8% compounded monthly” doesn’t actually earn you 8% over the year — it earns about 8.30%, because each month’s gain compounds. That higher figure is the effective annual rate, shown at the top of the results. When comparing two investments, compare their effective rates, not their headline rates.
The same logic powers the rule of thumb for doubling: divide 72 by your rate to estimate the years to double. At 8%, that’s about nine years, which the calculator confirms with an exact figure.
What return should you expect?
Higher expected returns come with higher risk. Cash and CDs are predictable but modest; a diversified stock portfolio has historically returned more over long periods but swings sharply year to year. Be honest about which you’re modeling — plugging a stock-market return into a savings-account plan will badly overstate your result.
Use the likely-range toggle to bracket an uncertain return, and lean conservative. It’s better to be pleasantly surprised than to build a plan on an optimistic number.
Frequently asked questions
What is a good annual investment return?
It depends on risk. Historically, a diversified stock portfolio has averaged around 7–10% a year over long periods, while safer options like CDs and high-yield savings return less. A “good” return is one that matches the risk you’re actually taking.
How do I calculate my investment return?
Total return is your ending value minus what you invested. To compare across time, look at the annual rate. The calculator above shows both the total and the effective annual yield from your inputs.
What is the average stock market return?
Broad U.S. stock indexes have returned roughly 10% a year on average before inflation, or around 7% after inflation, over very long periods — but with big swings in any given year. Plan with the after-inflation figure to stay realistic.
Is an 8% return realistic?
Over a long horizon for a stock-heavy portfolio, 8% is a reasonable average assumption — but expect individual years to be far higher or lower. Use the likely-range toggle to see the spread.