Is the calculator widget free to use?

Yes. It is free for any website, personal or commercial. The only condition is that you keep the visible attribution link to CompoundCalc that comes with the embed code.

Does the widget track my visitors?

No. The embedded calculator loads no analytics, no advertising and no third-party scripts. It runs entirely in the browser and sends nothing anywhere.

Will it match my site's design?

It follows your reader's light or dark system preference by default. You can also force light or dark, and switch the currency symbol between dollars, pounds and euros.

Can I set the starting numbers?

Yes. You can preset the initial amount, annual rate, number of years, monthly contribution and compounding frequency so the widget opens on the scenario your article is about.

Home › Calculators › Embed the Calculator

Free for any website

Embed the Compound Interest Calculator on Your Website

If you write about saving, investing or retirement, your readers usually want to try the numbers themselves. Drop this calculator into your post and they can, without leaving your page. Copy one block of HTML — no signup, no account, no script to install.

Free, including commercial useNo tracking, no ads inside the widgetWorks in WordPress, Ghost, Squarespace, plain HTML

1. Set it up

Change anything below and the preview and the code update together.

Theme

Currency

Max width (px)

Opening scenario — set these to match the example in your article.

Initial amount

Annual rate (%)

Years

Monthly contribution

Compounding

2. Check the preview

3. Copy the code

Paste this into a Custom HTML block in WordPress, or anywhere raw HTML is allowed.

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Please keep the attribution line. It sits under the calculator, it is one short sentence, and it is the only thing we ask for in exchange. Removing it is the one use we do not permit.

What you are actually embedding

No trackingThe widget loads no analytics, no advertising and no third-party scripts. Nothing about your readers is sent anywhere.

Self-containedOne HTML file, around 11 KB — under 4 KB compressed — with the styling and maths inside it. It pulls no fonts or libraries from anywhere.

Same maths as this siteIt runs the identical period-by-period projection used by our main calculator, verified against it across 5,760 scenarios.

ResponsiveIt reflows to the width you give it and works down to narrow phone screens.

Optional: let it resize itself

The fixed height in the code above is chosen to fit every screen size, so most people need nothing else. If you would rather the frame shrink to exactly the height it needs, add this script once, anywhere on the page.

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Terms, in plain English

Free, including on commercial and monetised sites. You do not need to ask us first.
Keep the visible attribution link. That is the whole price.
Do not re-host the widget file. Point the iframe at compoundcalc.com so bug fixes and improvements reach your readers automatically.
It is an educational estimate, not financial advice — the same disclaimer we apply to ourselves. Do not present its output as a guarantee or as regulated advice.
We may change or retire it. If we ever do, the URL will keep working or redirect somewhere sensible rather than break your page.

FAQ

Is it really free?

Yes, for personal and commercial sites alike. Keep the attribution link and you are done.

Does it slow my page down?

Barely. The embed code sets loading="lazy", so the browser only fetches the widget when the reader scrolls near it, and the file itself is under 4 KB compressed with nothing external to download.

Will it clash with my design?

By default it follows each reader's own light or dark preference. If your site is always one or the other, force it in the setup above.

Can I use it in a currency other than dollars?

You can switch the symbol to pounds or euros. The maths is currency-agnostic, so the projection is identical either way.

Can I preset the numbers to match my article?

Yes, and it usually works better that way. If your post is about investing £200 a month for 25 years, open the widget on exactly that and let readers adjust from there.

What if I want a different calculator?

Tell us which one. If there is demand we will build embeddable versions of the savings goal, rule of 72 and financial independence calculators next. Get in touch.

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