Decision trainer
It hands you the ordinary money decisions of a life: a raise, a car, a vacation, a bill you did not see coming, a market fall. With each one you watch four things move at once: your wealth, your cash flow, how good you feel about it, and what you have learned along the way.
Who it is for: If you know the math by heart and still cannot say why you decide what you decide, start here.
A date, not a total
You put in your income, your spending and what you have already invested, and out comes a single date: the day you stop needing a salary. Then it counts each fixed expense in the unit it really costs you, which is days of work.
Who it is for: If you are already saving and what you want to know is when you arrive, not how big the pile gets.
A century of real markets
You build a portfolio and run it through the returns that actually happened from 1920 onward: the Great Depression, the war years, 1970s inflation, the dot-com collapse, 2008, the pandemic. This is not a projection. It is what your portfolio would have lived through, had it existed back then.
Who it is for: If you have never watched your own portfolio go through a crash, here it is.
Probability, not an average
It runs your withdrawal plan through a thousand different futures, shuffling the order of the market years each time. Instead of a number you get a probability: how many of those futures the money actually lasted through.
Who it is for: If you already have a target figure and want to know how much margin is really left in it.
Income, stream by stream
You build an income stream out of six different sources (dividends, rent, interest, a business, royalties, a portfolio) and then try to live on it. That is where the differences between them stop being an idea and turn into a bill.
Who it is for: If "passive income" still sounds like one thing to you, this pulls it apart into four.
Where to start
If you turn up without a specific question, start with the Personal Finance Simulator: it asks you for nothing and shows you a decision moving inside of two minutes. The other four each answer one narrow question, so if yours is up there, go straight to it.
What happens to what you type
The math happens entirely in your browser, so nothing you type leaves your computer while you play. Three of the simulators keep a public ranking and the other two have a button that contributes your run; either way, something is only sent when you press it. And what gets contributed shows up aggregated and unnamed on the results page.
Data
If you want a figure rather than a game
A simulator shows you how a decision behaves; a calculator just hands you the number. If you already know what you want to work out, the calculators are the short way there. And if you hit a term you do not recognize inside a simulator, the glossary explains it.
See all the calculators ·
See the full glossary
