Embed our calculators on your site

The offer, with no fine print

A personal-finance blog explaining amortisation can put the mortgage calculator under the article. An Etsy seller writing a pricing guide can drop the fee calculator into it. A gym can host the BMI calculator on its membership page. In each case the reader finishes the job without leaving your site — which is the point.

• Free, with no account. No API key, no plan, no page-view limit, nothing to sign up for.
• No ads inside the frame. The embedded page carries no advertising code at all — just the calculator and the credit line.
• Works anywhere you can paste HTML. WordPress, Wix, Squarespace, Webflow, Shopify or a hand-written page — it is an ordinary <iframe>.
• Responsive. The frame fills the width you give it, up to 760 px, and collapses to one column on phones.
• The one condition: keep the credit paragraph that comes with the code, with its link to the full calculator.

That link is what pays for all this. It is a normal link — we do not force nofollow on you. Restyle, move or reword the paragraph to suit your page; just leave the link in place.

The offer is also available for our Spanish calculators and our Brazilian Portuguese calculators, each with its own picker.

Where to paste it

WordPress

In the block editor, click +, search for the Custom HTML block and paste the code into it. The block has a Preview tab, so you can check the frame before publishing. In the classic editor, switch to the Text tab — not Visual — or WordPress escapes the tags and the code shows up as text. On WordPress.com, custom HTML needs a paid plan; self-hosted WordPress has it on every install.

Wix

Use Add › Embed Code › Embed HTML, choose the Code option and paste. Wix puts the frame in a fixed-size box of its own, so drag the handles until the whole calculator is visible without an inner scrollbar — usually 700 to 900 px tall.

Squarespace

Add a Code block, set the mode to HTML and paste. Leave Display Source Code unticked, or the block prints the markup instead of rendering it.

Plain HTML, Webflow, Ghost and the rest

Paste both lines wherever the calculator belongs inside <body>. There is no script to load and nothing to install — the <iframe> brings everything with it. The loading="lazy" attribute means the browser only fetches the calculator as it nears the viewport, so the frame does not slow the rest of your page down.

What the embed is — and what it isn't

Dropping someone else's code into your site deserves suspicion, so here is exactly what you are adding.

It is an iframe, not a script. Nothing of ours runs in your page's context. The content is sealed inside the frame: it cannot read or change your HTML, touch your cookies, or affect your layout beyond the box you gave it.

The maths runs in your visitor's browser. No server does the calculating. What someone types is never sent anywhere and never stored — not by us, and not by you.

There is no advertising inside the frame. Embed pages are generated without any ad code. They also send X-Robots-Tag: noindex, so they never compete with your page in search results — your site is the one that gets indexed.

The height is your call. The generated code uses 700 px, which suits almost every calculator; if you see dead space or a cut-off result, change the number. To automate it instead, the framed page announces its own height to the parent window with postMessage, as { type: "brisktoolbox:height", height, tool }. Listening for it is optional:

window.addEventListener("message", function (e) {
  if (e.data && e.data.type === "brisktoolbox:height") {
    document.querySelector("iframe[src*='brisktoolbox']").height = e.data.height;
  }
});

What we don't promise. There is no SLA and no advance notice of changes. Calculators are updated when the underlying rules move — marketplace fee tables, IRS contribution limits, typical loan rates — and your embed always shows the current version. If a page is ever retired, its address redirects to the closest replacement rather than breaking.