Investment Portfolio Growth Calculator
Compare two investing strategies side-by-side and answer: Which scenario gives a better long-term result? Use different returns and contribution levels, and review both nominal and inflation-adjusted outcomes.
Methodology: deterministic formulas based on your inputs only. No account data, no external rates, and no personalized advice.
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Results
Solid: Scenario A (real) · Dashed: Scenario B (real)
Compare Scenarios
Save your current inputs and compare Current + up to 2 saved scenarios.
Note: Saved scenarios are stored locally in your browser.
No saved scenarios yet.
| Compare | Scenario | Saved | Actions |
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Compare
Select up to 2 saved scenarios to compare with Current.
Year-by-year schedule
| Year | A Real | B Real | B - A Real | A Nominal | B Nominal | B - A Nominal |
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How it works
Each scenario is projected month-by-month using your initial amount, monthly contribution, and expected annual return. Scenario A and B can use different assumptions.
Inflation-adjusted values are calculated by discounting nominal values to today’s money, so comparisons reflect purchasing power.
Important: This is a planning model. It does not include taxes, fees, or market volatility sequence effects.
What this scenario comparison reveals
This calculator is built for side-by-side strategy testing. It helps you compare how different contribution levels and return assumptions can widen or narrow long-term portfolio outcomes.
Instead of asking for one perfect forecast, use it to understand the size of potential outcome gaps between two plausible plans.
Key drivers of long-term portfolio gap
Monthly contribution size and time horizon are often the largest drivers. Return differences matter too, but consistent contributions can dominate outcomes over long periods.
Contribution timing (start vs end of period) creates a smaller but real effect because deposits made earlier have more time to compound.
How to interpret real vs nominal gap
Nominal gap shows raw account-value differences, while real gap adjusts for inflation and is often the better metric for planning purchasing power.
If nominal gains look large but real gains are modest, inflation is absorbing a meaningful portion of projected growth.
Frequently asked questions
What does inflation-adjusted mean here?
It means future values are shown in today’s purchasing power using the inflation rate you enter.
Can I compare conservative vs aggressive strategies?
Yes. Set Scenario A and Scenario B with different return and contribution assumptions, then compare the gap.
Does this guarantee real investment outcomes?
No. Returns are assumptions. Real markets vary year to year.