Choose the unknown
Use the mode tabs to solve for future value, required contribution, required return, starting amount, or time to target.
Investment planning calculator
Investment Calculator
Estimate how an investment may grow, what contribution may be required, what return would be needed, how much starting capital is needed, or how long it may take to reach a target.
Planning modes
Value / Contribution / Return / Time
Scenario math with fees, tax, and inflation context.
Investment inputs
Real-world adjustments
Results update automatically in your browser. No investment information is stored or sent to a server.
Estimated end balance
$0
Enter assumptions to estimate the investment result.
End balance after tax
$0
Total contributions
$0
Estimated gain
$0
Today's dollars
$0
Formula used
Investment value compounds the starting amount and periodic contributions by the selected return and frequency.
Accumulation schedule
Annual summary shows how starting amount, contributions, and gain build over time.
Starting amount
Contributions
Gain
How to use this investment calculator
Enter contribution assumptions
Monthly contributions are useful for recurring investing. Annual contributions are useful for bonuses, profit sharing, or once-a-year deposits.
Adjust for drag
Fees, taxes, and inflation can make a large difference over long periods. Use those fields when planning conservatively.
Read the schedule
The schedule separates starting amount, new contributions, estimated gain, and ending balance so the result is easier to audit.
Investment calculation method
This calculator uses fixed-rate compounding to model a simplified investment plan. The starting amount grows over time, and each contribution is added according to the selected timing and frequency.
When solving for required contribution, return, starting amount, or time, the calculator uses a numerical search against the target amount. This is practical because real-world options such as contribution timing, fees, and taxes make a single closed-form formula less flexible.
Future value = starting amount growth + contribution growth
The estimate is not a market forecast. It is a scenario tool that helps show how sensitive the outcome can be to time, return, contribution size, fees, taxes, and inflation.
Source and planning context
Investor.gov, from the U.S. Securities and Exchange Commission, provides a compound interest calculator and explains the core inputs investors commonly use: initial investment, monthly contribution, time horizon, estimated interest rate, and compounding frequency.
Practical examples
Monthly investing plan
A person investing every month can estimate the future balance and see how much comes from deposits versus compounded growth.
Target portfolio goal
If the goal is a specific future amount, the contribution mode estimates the recurring contribution needed to reach it.
Return sensitivity check
The return-rate mode helps test whether a target requires a conservative, moderate, or aggressive return assumption.
Related financial calculators
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- Payment Calculator for fixed-rate loan payment and payoff planning before investing extra cash.
- Amortization Calculator for seeing how debt payoff schedules change with extra principal payments.
Assumptions and limitations
This calculator assumes a fixed return rate and regular contributions. Real investments can have variable returns, losses, fees, spreads, taxes, liquidity limits, contribution limits, and behavioral risks.
The tax field is a simplified estimate applied to gains. It does not model account type, tax lots, qualified dividends, capital gains timing, retirement account rules, or local tax laws.
Data and source notes: This calculator does not use live market data. It applies the return, fee, tax, inflation, contribution, and timing assumptions entered by the user. For general investor education and compound interest context, compare assumptions with the linked Investor.gov resource in the methodology section.
Last reviewed: July 3, 2026. Editorial note: This page is built for transparent scenario planning, not investment recommendations.
FAQ
What return rate should I enter?
Use a conservative scenario that fits the asset mix and time horizon you want to test. Do not treat the input as a prediction.
Does compounding frequency matter?
Yes, but the difference is usually smaller than the impact of time, contribution size, and return assumptions. More frequent compounding produces a slightly higher effective rate when the stated rate is the same.
Why include inflation?
Inflation-adjusted value helps estimate purchasing power. A large future balance may buy less than expected if prices rise over time.
Can I use this for stocks, funds, real estate, or CDs?
You can use it for simplified fixed-return scenarios, but each asset type has different risk, fees, taxes, liquidity, and return behavior.
Why does the calculated required return look high?
A high required return usually means the target is aggressive for the starting amount, contribution level, and time horizon. Test a longer time period or higher contribution before relying on an aggressive return assumption.
Can this estimate monthly investment contributions?
Yes. Use the contribution mode to estimate the recurring monthly or annual contribution needed to reach a target amount under the return, fee, tax, and inflation assumptions entered.
Is this the same as an ROI calculator?
No. This tool projects a scenario over time with contributions and compounding. An ROI calculator compares investment gain against investment cost and is better for a completed or clearly defined investment outcome.
Does this calculator use live market prices?
No. It uses the return assumption you enter. It does not pull live stock, fund, bond, CD, real estate, or cryptocurrency prices.
This investment calculator is for general informational purposes and simple planning scenarios. It is not financial, investment, tax, legal, or retirement advice. Verify assumptions and decisions with qualified professionals.