About This Calculator
Projecting Your Investment Returns
Investment returns are never guaranteed. This calculator models three simultaneous scenarios so you can plan for different outcomes.
Three Scenarios
Pessimistic, base and optimistic returns shown side by side to help you plan for different outcomes.
Bear Markets Happen
Even strong long-term portfolios experience significant drawdowns. Plan for the pessimistic scenario.
Inflation-Adjusted Value
The real value column shows what your projected portfolio is worth in today purchasing power.
Worked Example
Elena invests 20,000 as a lump sum and adds 300 per month into a globally diversified index fund. She uses 7% as her base rate with a pessimistic scenario of 4% and optimistic of 10%. After 25 years: the pessimistic scenario gives 220,000, the base case 375,000 and the optimistic 630,000. The base case in real inflation-adjusted terms is approximately 230,000 in today purchasing power.
Common Questions
What return rate should I use for a diversified stock portfolio?
Global equity markets have historically returned 7-10% nominal annually. After inflation real returns are typically 4-7%. Use 5-7% as a base case.
How are the three scenarios calculated?
The pessimistic scenario uses 3% below your base rate the optimistic 3% above. These represent plausible long-term outcomes.
Does this account for investment fees?
No. A 1% annual fee on a 20-year investment reduces the final value by roughly 15-20%. Factor this into your rate assumption.
Should I invest a lump sum or spread it over time?
Research consistently shows that lump sum investing outperforms regular monthly investing approximately two-thirds of the time because markets tend to rise over time and money invested earlier has more time to compound. However regular monthly investing reduces the risk of investing a large sum just before a market crash and is more practical for most people building wealth from regular income.
Is my investment data stored anywhere?
No. All calculations are performed entirely in your browser. Nothing you enter — investment amounts, return assumptions, or personal financial details — is ever transmitted to our servers or retained in any form.