Is the investment calculator free?
Yes. It is completely free to use, with no signup, no account, and no paywall.
How accurate are the results?
The calculator uses the standard formulas for this kind of math, but real-world results can differ once fees, rounding, rate changes, and provider-specific rules come into play. Treat the output as a planning estimate, not a quote.
Does it stay local?
Yes. The numbers you enter are processed entirely in your browser and never leave your device.
Are contributions made at the start or the end of each month?
The end. The code uses an ordinary annuity, so each 200 deposit starts earning from the following month. If you actually invest on the first of the month, your real balance will be about one month's growth ahead of what the tool shows, roughly 0.58% at a 7% rate.
Does the projection account for inflation?
No, it is nominal throughout. The simplest fix is to subtract your inflation assumption from the return before you type it. Entering 4 rather than 7 gives you a figure roughly in today's purchasing power.
Where do I put fund fees?
Take them off the return rate. A fund returning 7% with a 1% expense ratio should be entered as 6, which on the defaults reduces the 20-year outcome from about 108242 to about 95697. That 12500 gap is what a single percentage point of fees costs.
What return rate is realistic to enter?
The tool takes no view. The 7% default is a common long-run nominal figure for a broad equity index before fees and before inflation, and it is a modelling assumption rather than a promise. Lower it for a bond-heavy allocation, and lower it again if you want a real rather than a nominal answer.
Is this a prediction of what I will have?
No, it is arithmetic. It compounds one constant rate over one horizon with no volatility, no fees, no taxes, and no inflation. It tells you what a set of assumptions implies, and nothing about whether those assumptions will hold.