What would it be worth if you'd started back then?
Investment Calculator replays a monthly investment plan with real historical market and currency movements, using your own numbers.
"What if I'd put $300 a month into the S&P 500 twenty years ago?" Find out, and see the market events you would have lived through along the way.
Replay monthly investing with past market data
Pick a start month, an initial amount, a monthly contribution, and an index, then tap "Start simulation."
- Four indexes: S&P 500, all-world equities, developed markets, and emerging markets
- See two lines — portfolio value and total contributions — plus your gain or loss. Touch the chart to read any month
- Choose from 16 display currencies. Outside the US, results include currency moves as well as stock prices
Change one assumption and run it again to see how much the start date or the monthly amount matters.
See what a crash did to your own balance
Play your results back over time. The balance counts up, and market events appear like subtitles.
Open an event to see your balance right before it, how low it went and when, and when it got back to where it was — in your money, not index percentages.
Work backward from a goal
On the "Goal" tab, set a target amount and a deadline, and the app works out what it takes to get there.
- Solve for the monthly contribution, the starting amount, or the annual return you'd need
- For the return, pick an index's historical rate or set your own
- Set the deadline as a date, or as an age, like "by the time my kid turns 18"
Turn a college fund or retirement goal into a concrete monthly number.
See it alongside your family's ages
Add yourself and your family with birth months, and follow the timeline by age.
- Switch the horizontal axis from year to age
- "Milestones" lists your balance and contributions at ages like 40 and 50
- Extend the period into the future to continue with a projection at the past rate. Projected months are labeled as such
Share it as a video
Tap "Share" to export your results as a vertical video, ready to send to family or post.
Choose whether amounts and ages appear before you export. Video sharing is free.
Why you can trust it
- No account needed
- Your scenarios, the people you add, and your history stay on your device, and calculations run on your device. None of it is sent to the developer's server
- The app only downloads market data, currency data, and event descriptions from the developer's server
- Free use may show Google AdMob ads
The indexes are synthetic series built from each index's total return (dividends reinvested) minus an assumed expense ratio. They are not the prices or returns of real ETFs or funds. Results are before tax and don't include taxes or account rules for plans such as a 401(k) or IRA. Past results and projections don't guarantee future returns, and this isn't investment advice. Data sources and assumptions are in "About the data and calculations" in the app.
Great for
- Seeing what years of monthly investing could add up to before you start
- Checking what you'd have today if you'd started in "that" year
- Seeing how a balance recovered after a crash when contributions kept going
- Figuring out a monthly amount for college or retirement savings
Pricing
Free for 10 runs in total, counting simulations and goals together. From the 4th run, every other run asks whether you'll watch an ad.
Premium removes ads and limits. Choose a monthly subscription or a one-time lifetime purchase. The price for your country is shown in the app before you buy.
After the free runs are used up, history, video sharing, and the data explanations stay available.
