A lump sum, regular contributions, or contributions that step up each year, compounded over time, with an optional inflation adjustment. Free to use on any site, with one line of HTML and nothing to sign up for.
This is the real widget. Try changing the numbers.
Calculator by smartfin.fyi
<iframe src="https://smartfin.fyi/embed/investment.html"
width="100%" height="1150" style="border:0"
title="Investment growth calculator" loading="lazy"></iframe>
<p style="font-size:12px;margin:6px 0 0">Calculator by <a href="https://smartfin.fyi/investment-calculator.html">smartfin.fyi</a></p>
Terms: there aren't many. Use it on any site, including commercial ones, at no cost. We may improve the calculator over time, so the embedded version can change. If it ever needs to be retired, this page will say so first.
The complete investment growth calculator on smartfin.fyi has more detail than the embed, including a full breakdown by year.