How much it shows over time
The same amount today, at your inflation rate, across the three destinations. Your years column is highlighted.
| Years | Cash (0%) | Bank (0.5%) | Fund (7%) |
|---|
Figures in today's purchasing power (already inflation-adjusted), for illustration only: neither inflation nor an index fund's return is constant year to year, only on average over the long run (see the historical returns simulator).
What each number means
A quick look at each field and result.
The money you have right now, whose future value you want to know.
How long you leave that money wherever it is, untouched.
How much prices rise each year on average. It's what makes the same figure buy less over time.
What that money earns each year, depending on where it sits: nothing if idle, little in a bank, more if invested.
The headline result: how much you'll be able to buy with that amount after those years, measured in today's dollars.
The same figure, three different fates: cash, a bank account, or an index fund — to see the cost of not investing at a glance.
How to fill out this calculator
Steps to see what happens to your money (expand)
- Enter the amount you want to study. It can be what you have saved today, or any figure to understand the effect.
- Choose the timeline in years. The longer it is, the more the gap between destinations shows.
- Adjust the average annual inflation. 2-2.5% is the typical long-run target of central banks, though some years spike well above it.
- Try the three "Where is your money?" buttons and compare the result: the gap between 0% and 7% return, sustained for years, is enormous.
- Read the table by years to see how the gap widens the longer time passes.
Frequently asked questions about this calculator
Why does cash lose value even if no one touches it?
Because its value isn't in the number, it's in what it can buy. If prices rise 2.5% a year and your money grows by nothing, that same bill buys a little less every year. Nothing dramatic needs to happen — time passing is enough.
Why does a bank account barely change the result compared to cash?
Because most checking and savings accounts pay interest far below inflation, often close to 0%. A 0.5% return against 2.5% inflation still loses purchasing power every year — just a bit slower than pure cash.
Why use 7% for the index fund?
It's a moderate assumption for the long-run nominal return of a globally diversified equity index portfolio, consistent with the other calculators on this site. No single year looks like the average: check the historical returns simulator to see the real path, ups and downs included.
Does this mean I should never hold cash or keep money in the bank?
No. Your emergency fund and money you'll need soon should stay liquid and stable, even if it loses some purchasing power — what matters there is having it available, not that it grows. This calculator is about money you won't need for a long time, which is exactly the money worth investing.
How does this relate to the compound interest calculator?
This one explains the problem: why idle money loses value. Compound interest explains the solution: how a sustained return doesn't just offset inflation, it actually grows your money.