Investment Calculator
This investment calculator shows how your money could grow over time based on your starting balance, regular contributions, and chosen annual return. Enter your numbers above to see your estimated future balance.
For example, if you start with $10,000 and contribute $500 a month at a 7% annual return, your balance grows to about $300,851 over 20 years. You put in $130,000, and compounding adds $170,851 in growth.
Investing calculators
How it works
The investment calculator above multiplies your contributions by a fixed annual return that compounds monthly. You provide a starting balance, a monthly contribution, an annual return rate, and a number of years. The tool then projects your ending balance and splits it into what you contributed versus what growth added.
Here is the key insight: in the example above, growth of $170,851 is larger than the $130,000 you contributed. Compounding means you earn returns on past returns, so over time growth can overtake your own deposits. The earlier you start, the bigger this effect becomes. This is an estimate — the calculator assumes one fixed annual return, but real markets rise and fall, so actual results will vary. Explore the compound interest calculator and investment growth calculator to go deeper.
Investment basics start with three building blocks. A stock is partial ownership in one company. An ETF holds a basket of stocks (or bonds) and trades like a single stock during market hours. An index fund tracks a benchmark like the S&P 500 and simply owns what the index owns — that is why fees are lower. Where you hold them matters too: a taxable brokerage account gives full flexibility but taxes gains each year, while a retirement account (401(k), IRA) defers or eliminates tax but locks the money until age 59½. The SEC's investor.gov guide recommends using tax-advantaged accounts first, then a brokerage for extra savings.
How to invest in stocks — a 4-step starter framework. First, open a brokerage or IRA account at a low-fee provider (no minimum, no trade commissions on stocks and ETFs). Second, buy a broad, low-cost S&P 500 or total-market index fund — one purchase gives you exposure to hundreds of companies. Third, automate contributions on payday so investing happens before you can spend the money. Fourth, ignore the daily headlines; the S&P 500 has returned about 10% a year on average since 1957 despite dozens of scary drawdowns along the way. Use the S&P 500 calculator to see what a steady contribution schedule would have produced. If you'd rather delegate the plan than DIY it, read our guide on how to choose a financial advisor before you sign anywhere.
Investment strategies worth knowing. Buy-and-hold owns the market long term and skips timing decisions. Dollar-cost averaging invests the same amount on a fixed schedule, which buys more shares when prices fall and fewer when they rise. Tax-advantaged prioritization means filling accounts in this order: employer 401(k) up to the match, then Roth or traditional IRA, then more 401(k), then a taxable brokerage. The order captures free money and tax breaks before flexibility. Once your accounts are funded, dividend-paying funds and interest-bearing accounts can become steady passive income streams that complement earned income.
Frequently asked questions
What is an investment calculator?
An investment calculator is a tool that projects how your money grows over time. You enter a starting amount, regular contributions, an annual return, and a time period. It then estimates your future balance and how much of it comes from growth versus your own deposits.
How accurate is this investment calculator?
The calculator gives an estimate, not a guarantee. It assumes one fixed annual return that compounds monthly. Real investment returns change year to year, so your actual balance could be higher or lower than the projection.
Why does growth eventually exceed my contributions?
Growth exceeds contributions because of compounding. You earn returns on your money and on past returns too. In the example above, $130,000 in deposits produced $170,851 in growth over 20 years, so growth outpaced what you put in.
Why does starting early matter so much?
Starting early matters because compounding needs time to build. The longer your money stays invested, the more returns stack on top of past returns. FINRA notes that even small investments can grow over time and benefit from compounding.
Which calculator should I use next?
Pick the tool that matches your goal. Try the compound interest calculator, the investment growth calculator, the high yield savings calculator, or the savings goal calculator. Modeling a systematic monthly contribution outside the U.S.? See the SIP calculator. Projecting a specific stock or ETF? Try the stock investment calculator. A federal employee? See the TSP calculator. Not sure which type of tool fits your question? Read how to choose an investment calculator. See all our free financial calculators.
I only have a little money to invest — is it even worth starting?
Yes, you can start investing with as little as $1. Many major brokerages, including Fidelity and Schwab, have a $0 account minimum. Both also let you buy fractional shares for as little as $1. That means you don't need thousands of dollars saved before you begin. Fractional shares let you own a slice of an expensive stock without buying a full share. Your starting amount matters less than consistency. Step three of the 4-step starter framework above is automating a small recurring contribution. Even $25 or $50 a month adds up if it happens automatically, before you can spend the money. See how steady small contributions add up over time with the dollar-cost averaging calculator.
Can this calculator model biweekly, quarterly, or increasing contributions?
Not directly. It applies one fixed monthly contribution across your entire timeline, with no separate input for biweekly or quarterly deposits, a one-time lump sum, or a contribution that steps up over time. For biweekly contributions, multiply your biweekly amount by 26 pay periods a year and divide by 12 to get the equivalent monthly figure to enter above. For quarterly, multiply by 4 and divide by 12. To model a raise or a planned increase, run the calculator once per contribution amount: enter your current monthly figure for the years until your next change, note the ending balance, then run it again using that ending balance as your new starting balance and the higher monthly amount for the next stretch. Chaining segments this way builds the same year-by-year schedule a spreadsheet with a changing contribution column would produce.
Does this calculator adjust for inflation?
No, this calculator projects nominal returns, not inflation-adjusted (real) returns. The annual return rate you enter compounds on its own without subtracting inflation's effect on purchasing power. To approximate a real return, subtract your expected inflation rate from your return rate before entering it, so a 7% nominal return minus roughly 3% average inflation is close to a 4% real return. A nominal projection answers what your account balance will actually read. A real return answers what that balance will be worth in today's dollars. For a closer look at where the nominal-vs-real gap comes from, and why some well-known 12% return assumptions skip it, see our breakdown of Dave Ramsey's 12% return rule.
What compounding formula does this calculator use?
This calculator compounds monthly using the standard future-value-with-contributions formula: FV = P × (1 + r)^n + PMT × [((1 + r)^n − 1) ÷ r], where P is your starting balance, PMT is your monthly contribution, r is your annual return divided by 12, and n is your number of months (years × 12). Enter the same P, PMT, r, and n into a spreadsheet's FV function, written as FV(rate, nper, -payment, -pv), and it reproduces the balance the calculator shows.
What does a 10-year example look like?
Using the same $10,000 starting balance and $500 monthly contribution from the example above, a 7% annual return over 10 years grows to roughly $106,600. You contribute $70,000 of that total, $10,000 upfront plus $500 for 120 months, and compounding adds about $36,600 in growth. Growth is a smaller share of the total than in the 20-year example above, because compounding needs more time to overtake your own deposits. Run the same inputs for 20 years instead and growth of $170,851 outpaces the $130,000 you put in.
Does this calculator include dividend reinvestment?
Only if you build it into the return rate you enter. This calculator applies a single blended annual return. It doesn't separately model price appreciation and dividend payouts. Enter a total-return rate, one that already assumes dividends are reinvested, rather than a price-only rate if you want dividends reflected in your projection. For a dedicated walkthrough of dividend reinvestment (DRIP) math and its tax caveats, see our dividend reinvestment calculator.
Does this calculator work outside the United States?
The calculator itself is USD-based and its examples use U.S. figures, but the compound-growth formula behind it works the same in any currency. Enter your own starting balance and contribution in your local currency and the math still applies. Just use your own country's typical investment return instead of the U.S. figures cited on this page. For appraisal math (NPV, IRR, payback period) that also applies globally, see our investment appraisal methods guide. To benchmark net worth internationally rather than project growth, see the international net worth calculator.
Do the 401(k), IRA, and TSP references on this page apply if I'm not in the United States?
No, the 401(k), IRA, and TSP accounts mentioned on this page are US-specific tax structures that have no direct equivalents abroad. While the calculator's compounding math is currency-agnostic, you should substitute your own country's tax-advantaged account rules rather than following the US funding order outlined here. If you project growth using our S&P 500 calculator, the historical return percentage applies universally, but the inputs and outputs are denominated in USD. You will need to convert your local currency contributions into US dollars, or convert the final balance projection back into your local currency, to make an accurate comparison.
Sources
We prioritize primary sources for rules, formulas, rates, limits, and definitions. See our calculator methodology and editorial policy.