Compound Investor
See how a scenario unfolds.
Explore compound growth, regular contributions, withdrawals and the effect of inflation over time.
Store downloads are not available yet.
Explore the assumptions behind the numbers
Build a scenario
Set a starting amount, a fixed annual growth assumption and a time horizon. Add weekly, monthly or yearly contributions, or switch to withdrawals to explore how long a balance might last under those assumptions.
Understand the timeline
Inspect individual years on the chart while keeping the final result in view. See nominal values alongside an inflation-adjusted view in today’s money. Inflation is an editable planning assumption, not a live rate.
Keep and share your plans
Save named scenarios locally with optional notes. Reopen, update or duplicate a saved plan to explore another set of assumptions. Share a projection image through your device’s share controls when you choose.
A simple workflow
Set assumptions
Choose amounts, frequency, growth, duration and inflation for an example you want to explore.
Explore
View the chart, inspect a year and change inputs to see how the model responds.
Save or share
Keep the scenario on your device, add a note, or share an image with a destination you choose.
A look inside the app
Current interface previews with synthetic data. Appearance may change before release.
The examples behind these previews
Illustrative scenarios; not forecasts or recommendations. Both examples use GBP, 20 years and a fixed 2% annual inflation assumption. Amounts are rounded to match the app’s display.
Long-term growth
Start with £10,000 and add £250 at the end of each month. Assume a constant 6% effective annual growth rate.
After 20 years, the model gives about £145k nominal, or £97.9k in today’s money after inflation. Total paid in: £70,000, including the starting amount.
Withdrawal scenario
Start with £250,000 and withdraw £1,000 at the end of each month. Assume a constant 4% effective annual growth rate, with no added contributions.
After 20 years, the model leaves about £184k nominal, or £124k in today’s money after inflation. Total withdrawn: £240,000. Different assumptions can exhaust the balance sooner.
The model applies growth each period before the contribution or withdrawal, using the equivalent periodic rate. “Today’s money” discounts the remaining balance by the assumed inflation over time. Neither value predicts what an investment will return.
A model for exploring possibilities
Results follow the inputs you choose. Growth and inflation stay constant throughout each scenario; actual markets and purchasing power vary. The model does not include taxes, fees, market volatility or changing cash flows.
This is an educational calculator, not financial advice, a recommendation or a guaranteed return. It does not connect to financial accounts or fetch live market, inflation or exchange rates.
Choose your display currency
Supported currencies: US dollar (USD), Indian rupee (INR), British pound (GBP), euro (EUR), Japanese yen (JPY), Australian dollar (AUD) and Canadian dollar (CAD).
Currency controls symbols, number formatting and input ranges; it does not convert amounts or perform FX conversion. When automatic inflation is selected, changing currency also chooses an editable planning default: 4% for INR, 2.5% for AUD and 2% for the others. These defaults are not live rates or forecasts.
Local plans, your choice to share
Calculations and saved plans work locally without an account. Saved names, optional notes and assumptions stay in the app’s device storage. Reopen a saved plan, update it, duplicate it or delete it from Saved.
Returning from the background keeps the current screen and work while the app process survives. A full restart opens a fresh unsaved scenario; saved plans, notes and preferences remain if the app’s data is intact. Save important changes before leaving.
Sharing is optional. The generated PNG includes the plan name, assumptions, chart and results, but excludes notes. A manual screenshot can show notes. Check the image and destination before sharing; copies outside the app follow that destination’s handling.
Deleting the app or clearing its data can lose saved plans. There is no in-app editable backup, import or cloud sync. A shared image is a readable record, not a plan you can restore. Read saved-plan guidance and the privacy policy.
Frequently asked questions
Are these numbers a forecast?
No. They are illustrations from fixed inputs. Actual returns vary, and taxes, fees and volatility are outside this model. Read the model limits.
Does changing currency convert my plan?
No. It changes display formatting and input ranges, without FX conversion. If automatic inflation is selected, it also changes the editable planning default. Review that assumption before comparing results.
What happens when I close or delete the app?
Background return preserves current work while the process survives. A full restart starts a fresh unsaved scenario and loads saved plans and notes. Deleting app data can lose those saved records. Check saved-plan guidance.
Will my notes appear in a shared image?
The generated projection PNG excludes notes, but includes the plan name, financial assumptions and results. Manual screenshots can reveal notes. Review what you share and who can receive it.
Which platforms can I use Compound Investor on?
iOS release availability is unconfirmed. A store link will be shown after verification.
Android is planned; a public store link will be added when that platform’s release is confirmed.
Get in touch
Have a question about Compound Investor? Contact Eternal Academy.