Investment Calculator
Monthly investing, replayed with real history
What if you had startedinvesting back then?
Pick a start month, a monthly amount, and an index. See what your plan would be worth today, using past S&P 500 and currency data.
Free for 10 runs · No account needed
- What would $300 a month for 20 years be worth now?
- How much should I save each month for college?
- What happened to my balance during a crash?
What you can do
Your numbers, real market history
Replay a plan with past data
Set a start month, an initial amount, and a monthly contribution, then tap "Start simulation."
- S&P 500, all world, developed, or emerging markets
- Value, contributions, and gain or loss for any month
- 16 display currencies, with currency moves included
Work backward from a goal
Set a target amount and a deadline on the "Goal" tab. The app works out what it takes.
- Solve for the monthly amount, starting amount, or return
- Use an index's historical rate or set your own
- Set the deadline as a date or an age, like when your kid turns 18
Follow it by your family's ages
Add yourself and your family with birth months, and read the timeline by age.
- Switch the horizontal axis from year to age
- "Milestones" lists your balance at ages like 40 and 50
- Extend into the future with a labeled projection
Share it as a video
Tap "Share" to export your results as a vertical video for family or social media.
- Choose whether amounts and ages appear
- Video sharing is free
Small amounts, every month.See where they could lead.
Replay
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 it in your money, not index percentages.
- 1Your balance right before the event
- 2How low it went, and when
- 3When it got back to where it was
How it works
Your first result in a few taps
- 1
Download for free
No account to create. Open the app and start.
- 2
Enter your plan
Start month, initial amount, monthly amount, and index.
- 3
Tap "Start simulation"
Read the chart, then change one assumption and run it again.
Privacy
Your plans stay on your phone
No account needed
No email and no sign up.
Calculated on your device
Scenarios, the people you add, and your history are stored on your device and never sent to the developer's server.
Only market data comes in
The app downloads market data, currency data, and event descriptions. Free use may show Google AdMob ads.
The indexes are synthetic series built from each index's total return minus an assumed expense ratio, not the prices of real ETFs or funds. Results are before tax and don't include plans such as a 401(k) or IRA. Past results and projections don't guarantee future returns, and this isn't investment advice.
Pricing
Try it free, upgrade only if you need more
Free
10 runs in total, counting simulations and goals together.
- From the 4th run, every other run asks if you'll watch an ad
- History, video sharing, and data explanations stay available after that
Premium
No ads and no limits. Choose monthly or a one time lifetime purchase.
- Cancel the monthly plan anytime in your store settings
- Restore purchases from inside the app
The price for your country is shown in the app before you buy.
FAQ
Questions before you download
Is Investment Calculator free?
Yes, for 10 runs in total. From the 4th run, every other run asks whether you'll watch an ad. Premium removes ads and limits.
Which indexes can I use?
S&P 500, all world equities, developed markets, and emerging markets.
Are these real ETF or fund returns?
No. Each index is a synthetic series built from the index's total return with dividends reinvested, minus an assumed expense ratio. Sources and assumptions are in "About the data and calculations" in the app.
Does it include taxes or a 401(k) or IRA?
No. Results are before tax and don't include the rules for any account type.
Can I see results in my own currency?
Yes. Choose from 16 display currencies. Outside the US, results include currency moves as well as stock prices.
Do I need an account? Is my data uploaded?
No account is needed. Your scenarios, people, and history stay on your device, and calculations run there too.
How do I cancel Premium?
Cancel the monthly plan in your App Store or Google Play account settings before the period ends. Deleting the app does not cancel it.
Is this investment advice?
No. Past results and projections don't guarantee future returns. Use it to explore scenarios.
Find out whatback then could have been
Free for 10 runs · No account needed