Frequently asked questions

Your inputs live in the page while you work. To revisit a scenario, note down your contribution, horizon, and allocation, or take a screenshot of the results dashboard.

Figures are shown in US dollars. The maths is currency-agnostic, so you can read the same numbers as your own currency if you contribute in it.

The simulator runs entirely in your browser. Your contribution amounts and allocations are not sent to a server or saved to an account.

No. It is a modelling tool, not a brokerage. It never asks for logins, account numbers, or the ability to move money.

Each asset preloads a long-run, rounded historical average as a starting point — for example roughly 10% a year for the S&P 500. These are editable estimates, not predictions, and you should adjust them to your own assumptions.

It runs hundreds of randomized market paths using your portfolio's expected return and volatility, then plots the range of outcomes. The shaded cone shows the spread between pessimistic and optimistic results, with a median line through the middle.

Inflation discounts future values back to today's purchasing power to give a 'real' figure. Taxes are applied to the gains on taxable assets at the rate you set; tax-advantaged buckets like a 401(k) are excluded from that calculation.

Small differences in compounding frequency, fees, contribution timing, and return assumptions add up over decades. The point is to understand the shape and sensitivity of outcomes, not to predict an exact dollar figure.

Check that your allocation weights add up to more than zero and that your contribution and horizon are above their minimums. A zero contribution or a 0-year horizon produces a flat line.

Very high return assumptions compound aggressively. Try lowering individual asset returns toward historical averages and increasing the inflation rate to see results in today's money.