Put a compound growth calculator on your site
One script tag adds Planomy's compound growth calculator to any page. It runs entirely in the visitor's browser: no cookies, no storage, no tracking, no requests to anyone but the widget file itself. Free to use on any site, commercial or not, as long as the "Powered by Planomy" link stays visible.
Live preview
This is the real widget, loaded exactly the way your page would load it. Resize the window to see it reflow — it responds to the width of its container, not the viewport.
Copy this
<script src="https://planomy.net/js/embed.js" data-planomy-embed="compound-growth" async></script>
The script replaces itself with an iframe at the point you place it and keeps that iframe's height in sync with the widget's content, so it never scrolls inside its own box.
Or use a plain iframe
If you would rather not run a script — many CMSs block them — the widget is a normal page and works in an iframe on its own. Set a height that suits your layout; roughly 640 px is enough on narrow columns and 420 px on wide ones.
<iframe src="https://planomy.net/embed/compound-growth.html"
title="Compound growth calculator by Planomy"
width="100%" height="640" style="border:0" loading="lazy"></iframe>
Options
All optional. Add them as attributes on the script tag, or as query
parameters on the iframe URL (?theme=dark&rate=6).
| Script attribute | URL parameter | What it does |
|---|---|---|
data-theme |
theme |
light or dark. Left off, the widget
follows the visitor's operating-system preference.
|
data-initial |
initial |
Starting balance in dollars. Default 10000. |
data-monthly |
monthly |
Monthly contribution in dollars. Default 500. |
data-rate |
rate |
Annual return as a percentage. Default 7. |
data-years |
years |
Years invested. Default 20. |
What it does and does not do
- The maths. It applies an effective monthly rate that compounds to exactly the annual return you enter over twelve months, with contributions added at the end of each month. Results are nominal (not inflation-adjusted) and before tax. It is the same model as the compound growth calculator on Planomy.
- Privacy. No cookies, no localStorage, no analytics, no network calls once the widget file has loaded. Nothing a visitor types leaves their browser.
- Accessibility. Every input is labelled, the sliders and fields are keyboard operable with a visible focus ring, and the result is announced to screen readers as it changes.
- Licence. Free to embed on any site, including commercial ones. Keep the "Powered by Planomy" link visible and followable. Do not present the widget as your own product or strip the attribution.
- Not advice. It is an estimate for planning intuition, not financial, tax or investment advice.
Questions, or want a different calculator packaged this way? See the full set — tell us which one you need and it can be added.