Investment Calculator
Estimate a portfolio's future value from a starting balance, monthly contributions, expected annual return, time horizon, and compounding frequency. Model beginning- or end-of-month deposits, annual contribution changes, portfolio fees, inflation-adjusted purchasing power, negative returns, and sensitivity scenarios. Review charts and export the complete year-by-year schedule.
A constant nominal scenario rate. Negative assumptions above -100% are supported.
The period is rounded to the nearest month.
This is a constant-return mathematical scenario, not a market forecast. Actual investments rise and fall unevenly.
Projected portfolio value
After 20 years using a smooth constant-return model.
- Total contributions
- $130,000
- Net growth
- $202,320
After modeled portfolio fees.
Inflation-adjusted value
Starting-year purchasing power using 2.5% inflation.
Modeled fee impact
$6,579 was directly deducted; impact also includes later return effects.
Fees, inflation, and scenario settings
Applied gradually to the modeled portfolio balance.
Used to calculate purchasing power in starting-year money.
Creates lower and higher return scenarios around the base return.
Changes the monthly contribution after each completed year.
Beginning-of-month contributions receive that month's modeled return.
Return summary
Gross effective return
Before the modeled portfolio fee.
Net effective return
After the modeled portfolio fee.
Real annualized return
After modeled fees and inflation.
Final monthly contribution
After annual contribution adjustments.
Projection charts and year-by-year schedule
Projected balance
Smooth constant-return scenario
Contributions and return
Composition of the projected portfolio value
- Total contributions
- $130,000
- Net investment growth
- $202,320
- Modeled fees deducted
- $6,579
Return scenarios
Sensitivity cases, not probabilities or forecasts
Lower
+6%
$255,744
Base
+8%
$332,320
Higher
+10%
$437,191
Year-by-year schedule
Balance, contributions, growth, fees, and purchasing power
| Year | Balance | Contributed | Net growth | Fees | Real value |
|---|---|---|---|---|---|
| 1 | $17,021 | $16,000 | $1,021 | $33.19 | $16,606 |
| 2 | $24,605 | $22,000 | $2,605 | $84.71 | $23,419 |
| 3 | $32,798 | $28,000 | $4,798 | $156.03 | $30,456 |
| 4 | $41,649 | $34,000 | $7,649 | $248.75 | $37,732 |
| 5 | $51,211 | $40,000 | $11,211 | $364.58 | $45,263 |
| 6 | $61,541 | $46,000 | $15,541 | $505.37 | $53,067 |
| 7 | $72,700 | $52,000 | $20,700 | $673.13 | $61,160 |
| 8 | $84,755 | $58,000 | $26,755 | $870.03 | $69,562 |
| 9 | $97,778 | $64,000 | $33,778 | $1,098 | $78,293 |
| 10 | $111,846 | $70,000 | $41,846 | $1,361 | $87,374 |
Showing checkpoints 1–10 of 20
Actual returns vary and can be negative. This model excludes taxes, trading costs, withdrawals, product-specific rules, and sequence-of-returns risk.
How to Use the Investment Calculator
Choose a display currency, then enter the money already invested, the amount planned each month, an expected annual return, and an investment period.
Select a compounding frequency for the nominal return. The main result shows the projected portfolio value, total personal contributions, net modeled growth or loss, inflation-adjusted purchasing power, and fee impact.
Open the advanced settings to change contribution timing, annual contribution increases, portfolio fees, inflation, and the lower-versus-higher scenario range.
The projection section contains a balance chart, contributions-versus-return breakdown, three sensitivity cases, a paginated yearly table, printing, and complete CSV export.
What This Investment Projection Models
The calculator applies a smooth constant return to a portfolio while adding monthly contributions. It is designed for scenario analysis rather than market prediction.
The annual return is converted using the selected compounding frequency and then expressed as an equivalent monthly rate so contributions can be processed consistently.
The ending balance includes the starting amount, all modeled contributions, investment gains or losses, and the effect of the entered portfolio fee.
Expected Return Is an Assumption, Not a Forecast
Actual investments do not earn the same percentage every year. Returns can be positive or negative, and the order in which gains and losses occur can materially change an investor's experience.
A constant-rate model is useful for comparing contribution plans and testing assumptions, but it cannot reproduce volatility, bear markets, recoveries, or sequence-of-returns risk.
Use several plausible cases rather than relying on one precise-looking future value.
How Return Compounding Is Handled
The annual return is treated as a nominal model rate. Annual, quarterly, monthly, or daily compounding determines its gross effective annual return.
The engine converts that effective annual return into an equivalent monthly rate before processing the monthly schedule.
For market portfolios, compounding frequency is a mathematical convention rather than a claim that the market credits interest at fixed boundaries.
Contribution Timing and Annual Increases
Beginning-of-month contributions receive that month's modeled return. End-of-month contributions are added after the month's modeled return and fee.
The annual contribution increase changes the monthly deposit after each completed year. Positive values model growing contributions, while negative values model a planned reduction.
The calculator does not enforce account-specific contribution limits, employer matching formulas, or missed deposits.
How Portfolio Fees Reduce Long-Term Value
The annual percentage fee is converted into monthly retention and applied gradually to the modeled balance.
Direct fees charged are only part of the cost. Once money leaves the portfolio, it also stops earning future returns. Fee impact therefore compares the complete no-fee and fee-adjusted projections.
Investor.gov explains that even small ongoing fees can have a substantial long-term effect because they reduce the amount left invested.
Nominal Balance Versus Inflation-Adjusted Value
Projected portfolio value is nominal: it is the number of currency units in the future account.
Inflation-adjusted value divides the nominal result by compounded inflation to express the balance in starting-year purchasing power.
The real annualized return shown by the calculator adjusts the modeled net return for inflation, but it does not include taxes.
Lower, Base, and Higher Return Scenarios
The scenario range subtracts from and adds to the base expected return, then reruns the complete model using the same contributions, fees, inflation, and timing.
These results show how sensitive the ending balance is to the return assumption.
They are not probabilities, confidence intervals, expected market ranges, or measures of investment risk.
How the three return scenarios are calculated
Swipe horizontally to view the full table.
Dollar-Cost Averaging and Regular Contributions
Regular monthly investing is often described as dollar-cost averaging: investing equal amounts at regular intervals regardless of market movement.
Regular contributions can support discipline, but they do not guarantee a profit or protect against losses.
This calculator models the contribution schedule but does not simulate changing market prices or the number of investment units purchased.
How to Read the Results
Total contributions include the starting balance and every modeled monthly deposit.
Net investment growth or loss equals the final balance minus total personal contributions after the entered portfolio fee.
Fee impact compares the no-fee and fee-adjusted ending balances. The yearly table also reports cumulative fees and inflation-adjusted value.
What each investment result means
Swipe horizontally to view the full table.
Model Assumptions and Real-World Differences
Every long-term projection depends on assumptions. The table separates the calculator's mathematical treatment from factors that make actual results different.
A suitable investment also depends on goals, time horizon, liquidity needs, debt, emergency savings, diversification, taxes, legal account rules, and risk tolerance.
Calculator assumptions versus real investing
The projection is transparent, but actual investment outcomes contain risks and costs that a smooth model cannot reproduce.
Swipe horizontally to view the full table.
Privacy and Appropriate Use
All calculations, charts, scenarios, and CSV data are produced locally in the browser.
The calculator is useful for comparing mathematical contribution, return, fee, and inflation scenarios.
Do not treat the output as a product recommendation, personalized financial advice, account statement, or guarantee of future performance.
Investment Projection Formulas
The engine converts the nominal annual return to an effective annual rate, derives an equivalent monthly rate, processes contributions, applies the recurring portfolio fee, and adjusts the final result for inflation.
Formula variables
- Nominal annual return as a decimal
- Compounding periods per year
- Gross effective annual return
- Equivalent monthly return
- Annual portfolio fee as a decimal
- Contribution made in month t
- Annual inflation assumption
- Investment period in years
- Portfolio balance after month t
Examples
Starting balance plus monthly investing
1Input
$10,000 starting balance; $500 per month; 8% nominal return; monthly compounding; 20 years.
Show result
Result
The tool separates the projected portfolio value into total contributions and modeled net growth.
Adding a fee and inflation rate also shows fee drag and starting-year purchasing power.
Compare contribution timing
2Input
Run the same plan with beginning-of-month deposits and end-of-month deposits.
Show result
Result
Beginning contributions finish slightly higher because each deposit receives one additional month of modeled return.
Increase monthly investing over time
3Input
$500 monthly contribution with a 3% annual contribution increase.
Show result
Result
The modeled monthly deposit rises after every completed year, and the final monthly contribution appears in the advanced results.
Measure long-term fee impact
4Input
Compare a 0.10% annual portfolio fee with a 1.00% fee over 30 years.
Show result
Result
Fee impact compares complete no-fee and fee-adjusted balances, including future return lost on deducted fees.
Test a negative return
5Input
Expected annual return -5% with continuing monthly contributions.
Show result
Result
The calculator models a declining return path while continuing to add contributions.
Compare sensitivity scenarios
6Input
Base return 7% and scenario range ±2 percentage points.
Show result
Result
The tool reports complete lower, base, and higher projections at 5%, 7%, and 9%.
Frequently Asked Questions
Is the projected investment balance guaranteed?
No. It is a smooth mathematical scenario. Actual returns fluctuate and can be lower, higher, or negative.
How do I calculate investment growth with monthly contributions?
Enter the starting balance, monthly contribution, expected annual return, time horizon, and compounding frequency. The calculator adds each monthly deposit using the selected timing.
Why does the calculator allow a negative annual return?
Investments can lose value. Negative assumptions make it possible to test how contributions and time behave during a poor-return scenario.
What does return compounding mean in this calculator?
It converts the nominal annual return into an effective annual rate. The engine then derives an equivalent monthly rate for the monthly schedule.
Are contributions made at the start or end of the month?
You can choose. Beginning contributions receive that month's modeled return; end contributions are added afterward.
How are investment fees calculated?
The annual portfolio fee is converted into monthly retention and applied to the modeled balance. Fee impact also includes the future return lost on deducted amounts.
Does the calculator include taxes?
No. Taxable distributions, capital gains, deductions, credits, account types, and withdrawal taxes are not modeled.
What is inflation-adjusted value?
It is the future portfolio balance expressed in starting-year purchasing power using the constant inflation rate entered.
What does real annualized return mean?
It is the modeled net effective annual return adjusted for inflation. Taxes are not included.
What is the return scenario range?
It subtracts and adds the entered number of percentage points to the base return and reruns the model. It is not a probability range.
Can I use this for stocks, ETFs, or mutual funds?
It can model a broad smooth return assumption, but it does not reproduce a product's volatility, distributions, taxes, fees, or tracking differences.
Does monthly investing remove market risk?
No. Regular investing can support discipline, but it does not guarantee profit or protect against losses.
What is sequence-of-returns risk?
It is the risk that the order of gains and losses changes the outcome, especially when money is entering or leaving a portfolio. A constant-return model does not simulate it.
Can I export the investment schedule?
Yes. The complete checkpoint schedule can be exported as CSV even though the on-page table is paginated.
Are my investment assumptions uploaded?
No. Calculations, charts, and CSV creation occur locally in the browser.
References
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