Investment Calculator
See what your investments could become. Set a starting amount, monthly contribution, expected return and time horizon, and watch compound growth build month by month — with charts, an inflation-adjusted real value, and a projection you can download as CSV or PDF. It all runs in your browser, so your figures stay on your device.
- 🔒 100% private — no uploads
- 🆓 Free, no watermark
- 📱 Works on any device
How to project your investments
- 1
Enter your plan
Set a starting amount, monthly contribution, expected annual return and how many years you’ll invest. The projection updates as you type, all in your browser.
- 2
Tune for inflation & raises
Optionally increase your contribution each year (for raises) and set an inflation rate to see the real, in-today’s-money value of your future balance.
- 3
Watch it compound
See compound growth build month by month, with a chart of contributions versus growth and a donut showing how much of your balance is earnings.
- 4
Download your projection
Save every month as a CSV, or a one-page PDF report with the growth chart and a yearly breakdown — produced entirely on your device.
Why use Investment Calculator?
100% private
Your balances, contributions and goals stay on your device. Nothing is uploaded and there’s no sign-up.
Compound growth, month by month
Interest compounds on your running balance every month, so you see the curve that contributions plus time really produce.
Inflation-adjusted
Set an inflation rate to see the real, in-today’s-money value of your future balance alongside the nominal figure.
Download projections
Export the full month-by-month projection as CSV, or a one-page PDF report with the chart and a yearly breakdown.
How compounding builds wealth
Compounding means your returns earn returns. Each month, your balance grows by its return and then your new contribution is added; next month, the larger balance earns even more. Over years this turns a steady habit into a curve that bends sharply upward. The chart splits your final balance into what you contributed versus what growth added, so you can see how much of the result is compounding rather than your own deposits.
Contributions matter as much as returns
Early on, your contributions drive most of the growth; later, compounding takes over. That’s why starting sooner and contributing consistently is so powerful — even at a modest return. Try raising your monthly contribution, or turn on an annual contribution increase to model raises, and watch how much the final value changes.
Frequently asked questions
Do my numbers get uploaded anywhere?
No. Every calculation runs entirely in your browser — your income, loan amount, balances and goals never leave your device. There’s no account and nothing is sent to a server.
What return rate should I use?
That’s up to you. Many people model a long-run stock-market average of around 6–8% per year, but returns aren’t guaranteed and vary year to year. Try a few rates to see a range of outcomes.
Can it adjust for inflation?
Yes. Set an inflation rate and the calculator also shows the “real” value of your future balance — what it would be worth in today’s money.
Can I download the month-by-month numbers?
Yes. You get the full schedule as a CSV you can open in Excel or Google Sheets, plus a one-page PDF summary with the chart and a yearly breakdown — both generated on your device.
Are these results financial advice?
No. These are estimates to help you explore scenarios. Real loan and investment outcomes depend on terms, fees, taxes and market returns that vary — always confirm with your lender or a qualified advisor.