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Embed platform · Free forever

Drop any of 220 calculators on your site in two clicks.

One iframe. Three sizes. Four themes. Custom currency. WordPress plugin. Auto-resizes to its content. No signup, no JavaScript dependencies, no fees, no ads inside the widget — and the math, AI insight, and UI stay perfectly in sync with the live calculator.

Open the embed builderWordPress plugin (alpha)
3 sizes × 4 themes

Pick a size, pick a theme — done.

Every calculator declares which sizes it supports. Multi-input wizards opt out of mini; decision-style calcs (job-offer, lease-vs-buy) keep all three.

Full

Complete calc — inputs, result, AI insight, every detail row.

Compact

Inputs + result only. AI insight + advanced rows hidden.

Mini

Single primary input + headline result. Sidebar / promo strips.

Themes
  • Auto
  • Light
  • Dark
  • Brand
  • ?accent={hex}
Live preview

This is exactly what your visitors see.

The iframe below loads the same /embed/percentage-calculator URL the code snippets generate. Resize your browser — the embed auto-resizes to fit.

Pick your calculator → grab the code

The 12 most-embedded calculators below. Want a different one? Open any of the 220calculator pages — the “Drop this on your site” strip is one click from the result.

Three formats. Same calculator.

The embed builder hands you ready-to-paste code.

  • HTML iframeUniversal
    <iframe
  src="https://calcbold.com/embed/percentage-calculator"
  width="100%"
  height="820"
  loading="lazy"
  style="border:0"
></iframe>
  • JS loader (auto-resize)Recommended
    <div data-calcbold="percentage-calculator"></div>
<script async
  src="https://calcbold.com/embed.js">
</script>
  • WordPress shortcodePlugin
    [calcbold slug="percentage-calculator"
  variant="full"
  theme="auto"]

All three resolve to the same calculator. The JS loader is recommended — it auto-resizes the iframe via postMessage.

Why CalcBold embed beats hand-built widgets

Always up to date

Calculator improvements ship to every embed automatically. Never re-paste code, never patch a bug across 30 sites.

Auto-resizes

Posts its height via postMessage; the loader script resizes the iframe to match the content. No scrollbars, ever.

Privacy-first

Calculation runs inside the iframe. No visitor data leaves their browser. AdSense-safe by design — zero ads in /embed/*.

Fast

Iframe loads lazily, served from Cloudflare edge cache. Zero impact on LCP/CLS, negligible on INP.

Works everywhere you can paste HTML

Tested on all eight platforms below. If your CMS allows raw HTML or a script tag, the embed works.

  • WordPress
  • Webflow
  • Framer
  • Notion
  • Substack
  • Ghost
  • Squarespace
  • Hand-coded HTML

Ready to drop one on your site?

Pick the calculator your audience actually needs — the rest takes 30 seconds.

Open the embed builderDownload WP plugin

Frequently Asked Questions

The most common questions we get about this calculator — each answer is kept under 60 words so you can scan.

  • How fast can I actually embed a calculator?
    Two clicks plus paste. Click your calculator on this page, click the format you want (HTML iframe, JS loader, or WordPress shortcode), paste into your page editor. The widget renders the same calculator your visitors use on calcbold.com — same math, same AI insight, same UI.
  • Will my visitors see ads inside the embed?
    No. The /embed/* surface is ad-free by design — both for cleaner UX on your site and to comply with AdSense's 'widget designed to leech revenue' policy. Ads run on the main calc page only, where the 'Powered by CalcBold' click-through lands.
  • Is this really free? What's the catch?
    Free forever for the embed itself, the resize loader, the API behind every answer, and the platform. The only ask is a subtle 'Powered by CalcBold' link in the embed footer — and you can remove it on a Pro plan when Phase M ships ($9/mo). The free tier is the product, not bait.
  • Does it work on WordPress / Webflow / Substack / Notion / Ghost?
    Yes. The HTML iframe snippet works on any host that allows raw HTML — Webflow custom-code blocks, WordPress Custom HTML block, Substack Pro, Ghost, Squarespace code blocks, hand-coded sites. The JS loader works when iframes are stripped but scripts allowed. WordPress also has a dedicated plugin with a [calcbold] shortcode (alpha — download below).
  • How does the embed affect my Core Web Vitals?
    Iframe loads lazily (loading="lazy") and is served from Cloudflare edge cache. The resize loader is < 1 KB gzipped, deferred, and cached for 24 h. Net impact on LCP/CLS: zero. On INP: negligible. The widget is designed to be a good citizen on host pages — that's why we engineered the /embed surface as a separate route group with its own headers.
  • Can I customize the look — colors, fonts, dark mode?
    Yes. Every embed accepts ?theme=light|dark|auto|brand and ?accent={hex} URL parameters. Auto follows the visitor's prefers-color-scheme. Brand replaces the primary color throughout the calculator. The fonts inherit from the iframe (we use system stacks inside the embed so it blends with your typography).
  • What about iframe security on my site?
    We send Content-Security-Policy: frame-ancestors * on the embed surface and strip X-Frame-Options so any host can embed. Sandbox attribute is supported if you want to restrict further. The embed never runs scripts on the parent page; the resize loader is read-only postMessage with origin checks.
  • Can I get support if something breaks on my site?
    Email [email protected] — typical response under 24 hours weekdays. Pro and Business tiers ship in Phase M with priority support and dedicated channels.