Investment Calculator
Project the growth of an investment.
Results update as you type.
This calculator is for illustrative purposes only. Actual rates, fees and terms vary by lender. Consult a qualified financial adviser before making borrowing decisions.
How it works
The future value shown here is the projected worth of a portfolio that starts with a lump sum and receives steady monthly contributions, all growing at your expected annual return. It matters because it turns an abstract savings habit into a concrete target: you can see what regular investing might become over a decade or two and how much of that balance is your own money versus compounded earnings. This investment calculator grows the starting amount and each contribution at the monthly equivalent of your annual return, then sums them, because a real portfolio earns returns that are themselves reinvested to earn more — the engine of long-term growth. The future-value formula is used precisely because it captures that reinvestment, treating the initial sum as compounding and the contributions as a monthly annuity added on top. Individual investors, retirement savers and advisors use an investment calculator to set contribution levels, test how sensitive the outcome is to the assumed return, and weigh investing a windfall now against drip-feeding it over time. Since markets rise and fall and no return is guaranteed, treat any figure from an investment calculator as a nominal, pre-tax planning estimate; running a conservative and an optimistic rate brackets the realistic range better than trusting a single projection.
FV = P(1 + i)^n + PMT × [((1 + i)^n − 1) ÷ i], i = annual ÷ 12
P is the initial investment and i is the monthly return, so P(1 + i)^n compounds the lump sum across n months. Each monthly contribution PMT is its own small deposit that compounds for the months remaining, and the bracketed annuity term ((1 + i)^n − 1) ÷ i sums all of them. Adding the two gives the total. The exponential factors capture returns being reinvested, which is why later years contribute so much more growth than early ones.
Source:U.S. SEC — Investor.gov
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter initial investment, annual return and years.
- 2
Adjust the options
Adjust monthly contribution if they apply — sensible defaults are already set.
- 3
Read your result
Future value updates instantly as you type — no button to press.
Frequently asked questions
What annual return should I assume?
It depends entirely on what you hold. A broad, diversified stock index has historically averaged roughly 7–10% a year before inflation over long periods, while bonds return less and cash barely keeps pace with prices. A balanced portfolio sits in between. Choose a rate that matches your actual mix, and lean conservative for planning. Past performance is not a promise, so test a lower rate to see the downside.
Does this account for inflation and taxes?
No. The projection is nominal and pre-tax, meaning it shows dollars without adjusting for rising prices or the tax owed on gains. Real purchasing power will be lower — at 3% inflation, money roughly halves in value over 24 years. Taxes further reduce returns unless the money sits in a tax-advantaged account like an IRA or 401(k). Subtract an estimate for both to gauge what the balance will truly buy.
How accurate is an investment calculator?
The arithmetic is exact, but the result is only as good as the return you assume. Real markets do not deliver a smooth, constant rate; they swing, and the order of good and bad years affects outcomes the model cannot show. Treat the figure as a reasonable midpoint for planning, not a forecast. Running several rates and revisiting the projection as your contributions and markets change keeps it useful.
Is it better to invest a lump sum or contribute monthly?
Mathematically, investing a lump sum sooner usually wins, because the full amount compounds for longer. In practice, spreading contributions — dollar-cost averaging — reduces the risk of buying everything just before a downturn and suits people paid monthly. This tool models both at once: a starting amount plus ongoing deposits. If you have a windfall and a long horizon, investing more of it early tends to produce the larger balance.
How often are contributions compounded here?
Monthly. Each contribution is treated as an end-of-month deposit that then compounds at the monthly equivalent of your annual return for the rest of the period. This mirrors how most people actually invest — a fixed amount from each paycheck — and how brokerage and retirement accounts credit growth. Compounding more frequently than monthly changes the result only marginally, so the monthly convention is both realistic and accurate enough for planning.