Start with credible inputs
Use conservative expected returns, realistic contributions and an inflation assumption. Change one input at a time so you know what drives the output.
LONG-TERM INVESTMENT · LEVEL 2–4
Make the future
an honest scenario.
Set the assets, weights, contributions, return assumptions and time horizon. Then compare the portfolio’s nominal path with its purchasing power in today’s dollars.
FUTURE SCENARIO
Send your allocation into the next N years.
This is an adjustable planning scenario, not a market forecast. Write down assumptions you could actually live with.
Asset allocation and return assumptionsEvery asset has its own weight and adjustable nominal annual-return assumption. Add as many Other assets as you need for your own scenario. These are scenario inputs, not promises about the future.
MSCI ACWI ACWI
MSCI World URTH
FTSE All-World VT
S&P 500 SPY
Nasdaq-100 QQQ
Intermediate Treasury bonds IEF
Long Treasury bonds TLT
Gold GLD
Broad commodities DBC
Global listed REITs REET
Bitcoin BTC-USD
Current total: 100.0%
Projected value in year N$59,083
Year N in today’s dollars$32,618
Starting weighted expected return6.1%
ONE POSSIBLE FUTURE
What could your portfolio grow into?
Nominal valueIn today’s dollars
Year-by-year projection
| Year | Nominal value | Today’s dollars |
|---|---|---|
| 0 | $10,000 | $10,000 |
| 1 | $10,610 | $10,402 |
| 2 | $11,257 | $10,820 |
| 3 | $11,944 | $11,255 |
| 4 | $12,672 | $11,707 |
| 5 | $13,445 | $12,178 |
| 6 | $14,266 | $12,668 |
| 7 | $15,136 | $13,177 |
| 8 | $16,059 | $13,706 |
| 9 | $17,039 | $14,257 |
| 10 | $18,078 | $14,830 |
| 11 | $19,181 | $15,426 |
| 12 | $20,351 | $16,047 |
| 13 | $21,592 | $16,692 |
| 14 | $22,909 | $17,363 |
| 15 | $24,307 | $18,060 |
| 16 | $25,790 | $18,786 |
| 17 | $27,363 | $19,542 |
| 18 | $29,032 | $20,327 |
| 19 | $30,803 | $21,144 |
| 20 | $32,682 | $21,994 |
| 21 | $34,676 | $22,878 |
| 22 | $36,791 | $23,798 |
| 23 | $39,035 | $24,754 |
| 24 | $41,416 | $25,749 |
| 25 | $43,942 | $26,784 |
| 26 | $46,623 | $27,861 |
| 27 | $49,467 | $28,981 |
| 28 | $52,484 | $30,146 |
| 29 | $55,686 | $31,357 |
| 30 | $59,083 | $32,618 |
Scenario notes: The tool converts each entered nominal annual return into a constant monthly return and draws a deterministic planning path; real markets will not be this smooth. Nominal values do not subtract inflation, while today’s-dollar values use your inflation assumption. Taxes, fund fees, trading costs, currency effects, withdrawals and losses are not included. This is not investment advice.
HOW TO USE THIS
A projection is a rehearsal,
not a promise.
Use conservative inputs, then change one assumption at a time. The useful question is not whether a smooth line will happen; it is whether your plan still makes sense when reality is less smooth, more expensive or slower than your spreadsheet.
INVESTMENT PORTFOLIO GROWTH CALCULATOR EXPLAINED
What could your custom portfolio grow to after contributions and withdrawals?
The forecast turns an asset mix, return assumptions, contributions, withdrawals and time horizon into a transparent scenario in both nominal money and today’s purchasing power.
How to interpret the calculator result
Read the result in context
Compare nominal value with inflation-adjusted value. The gap shows why a large future currency amount may fund less real spending than it appears to today.
Turn it into a decision
Use low, base and high assumptions to define a planning range, then improve the inputs you can control rather than treating the midpoint as a promise.
COMMON QUESTIONS
Questions about this investment portfolio growth calculator.
What return should I use for a portfolio forecast?
Use a conservative assumption consistent with the assets and fees in your portfolio, then test lower outcomes. A forecast is more useful as a range than as one precise return.
Why show today’s dollars?
Inflation reduces purchasing power. Today’s dollars translate the future balance into an amount that is easier to compare with current spending.
MODEL & DATA CARD
Inspect the calculation before trusting the result.
What this tool answersShows one deterministic path implied by the user's return, contribution, withdrawal and inflation assumptions. It is a planning calculator, not a probabilistic market forecast.
Calculation method
Converts each nominal annual return to a constant monthly rate, applies contributions before each month's growth, and restores target weights at the chosen frequency. Once withdrawals begin, new contributions stop; withdrawals occur at year-end. Real values divide nominal balances by compounded user-entered inflation.
Data lineage
There is no external market dataset or live forecast. Asset labels and default returns are editable starting assumptions; every result is generated locally from the visible inputs.
Visible checks
The table exposes every annual nominal and real balance. Setting inflation to 0% makes both paths equal; setting every return and cash flow to 0 keeps the starting balance unchanged.
Important omissions
Constant returns erase volatility, sequence risk and correlations. Taxes, fees, spreads, currency changes and unexpected cash flows are absent. A smooth path can look safer than any investable path would be.
Primary references and data origin
External sources explain the data or method; they do not endorse Rich2Fire or its outputs.
EVIDENCE SNAPSHOT
What this tool is built on.
Custom Portfolio Forecast. Builds one deterministic path from user-entered returns, contributions, withdrawals, rebalancing and inflation assumptions.
This is implementation evidence, not professional certification. Assumptions and limits matter more than a badge. Correction policy.
- Model version
- 1.0
- Last reviewed
- Evidence basis
- Transparent planning scenario using your inputs
- Data status
- No live feed; results change only with your inputs
- Decision sensitivity
- Financial assumptions matter
CITE THIS TOOL
Let readers return to the same version.
This citation includes the tool name, model version, review date and stable URL. Citation does not imply Rich2Fire endorses third-party content.
Rich2Fire. (2026). Custom Portfolio Forecast (model version 1.0, reviewed 2026-10-10). https://rich2fire.com/tools/custom-portfolio-forecast