Investment Calculator
Project what an investment could grow to, or work backward to the rate, deposit, starting amount or number of years you need to hit a goal. Set the compounding frequency, choose monthly or yearly deposits at the start or end of each period, and see the balance split into contributions and compound growth, year by year, with an optional inflation-adjusted value.
Formula
Worked example
$10,000 start, $500/month, 7% return compounded annually, 20 years -> annual factor 1.07, FV about $295,000, of which about $130,000 is contributions and about $165,000 is growth. Switch "Solve for" to Years to see it takes roughly 28 years to reach $500,000 at the same inputs.
How investment growth is calculated
This tool combines two standard formulas: the future value of your starting lump sum, P times (1 + i) to the power t, and the future value of a stream of equal contributions. Here i is the effective annual return implied by your nominal rate and compounding frequency, and t is the number of years. Each contribution grows from the moment it is deposited, so the calculator converts the annual growth factor into a per-deposit factor based on whether you contribute monthly or yearly. Adding the two pieces gives the projected balance, and subtracting everything you contributed leaves the growth earned by compounding.
Compounding frequency and contribution timing
Compounding frequency sets how often returns are added back to the balance: annually, semiannually, quarterly, monthly, daily, or continuously. More frequent compounding raises the effective annual return slightly for the same nominal rate. Contribution timing matters too. End-of-period deposits (an ordinary annuity) are the default, while start-of-period deposits (an annuity due) each earn one extra period of return, which nudges the final balance up. Use the contribution frequency control to switch between monthly and yearly deposits.
Solving backward for a goal
Beyond projecting a future value, this calculator can reverse-solve for any single unknown. Set a target end amount and let it find the annual return rate you would need, the starting amount to begin with, the monthly or yearly contribution required, or the number of years it would take. The rate and years solvers use a numerical search because those variables sit inside an exponent and cannot be isolated with simple algebra. This makes it easy to turn a savings goal into a concrete monthly habit.
Inflation and a realistic return
Historically, a globally diversified stock portfolio has returned roughly 6-8% per year on average before inflation, with individual years ranging from sharply negative to strongly positive. Bonds and cash typically return less. The headline figures here are nominal (face value); turn on the inflation adjustment to also see the balance in today’s purchasing power, which discounts the future value by your assumed inflation rate. Treat every figure as a smooth long-run projection, not a forecast of any single year.
Long-run average returns by asset class
| Asset class | Typical long-run return | Risk level |
|---|---|---|
| Cash / money market | 1-3% | Very low |
| Government bonds | 2-4% | Low |
| Corporate bonds | 3-5% | Low to moderate |
| Diversified stocks | 6-8% | Moderate to high |
| Single stocks | Highly variable | High |
Rough nominal pre-inflation averages for planning; actual returns vary widely year to year.
Frequently asked questions
What can this calculator solve for?
Five things. Leave "Solve for" on Future value to project an end balance, or switch it to find the required annual return, the starting amount, the monthly or yearly contribution, or the number of years needed to reach a target end amount. Fill in the remaining fields and the calculator works backward to the unknown.
Does compounding frequency change the result?
Yes, but modestly. For the same nominal rate, compounding more often (monthly or daily instead of annually) raises the effective annual return a little, so the final balance is slightly higher. Continuous compounding is the theoretical upper limit. The default is annual compounding.
Are contributions added at the start or end of the period?
You choose. The default is end of period (an ordinary annuity). Switching to start of period (an annuity due) makes each contribution earn one extra period of return, which raises the final balance slightly.
Does this account for inflation?
The headline numbers are nominal (face-value) dollars. Turn on the inflation adjustment to also see the balance in today’s purchasing power, which discounts the future value by your assumed inflation rate. As a quick alternative, you can subtract your inflation rate from the return rate instead.
Is the return guaranteed?
No. Real returns vary year to year and can be negative. This calculator assumes a constant average rate to illustrate the long-run effect of compounding, not to forecast an exact balance.