Unit converter — free for any website

Length, weight and temperature conversions.

Micro-tools

Use it now — freeWhy free? See how this compares to Elfsight →
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What is Unit converter?

Unit converter is one of 590+ free widgets on PlanckUi. Length, weight and temperature conversions. Small interactive utilities give visitors a reason to stay, return and bookmark you.

Perfect for sidebars, tool pages and resource collections.

Everything is rendered in an isolated shadow DOM, so it can never conflict with your site's own styles — and at a few kilobytes, it won't move your page speed.

Everything included

  • Length, weight and temperature conversions.
  • Free forever — no watermark, no usage limits, no "upgrade to remove"
  • Customize everything: colors, fonts, corner radius, shadows, dark mode
  • Copy-paste install: one snippet of HTML works on any website builder

Add Unit converter to your website in 3 steps

  1. Customize it. Use the Paint editor right on this page — set your colors, fonts, radius and content. Unit converter updates live as you change things.
  2. Copy the HTML. One click gives you a self-contained snippet. No account needed, nothing to install, no script from our servers.
  3. Paste it on your site. Paste it anywhere HTML goes: your site, a landing page, WordPress, Webflow, Wix, Squarespace, Shopify, Ghost — if it renders HTML, it works.

Unit converter is free on PlanckUi — the same embed runs $15–40/month on Elfsight or Common Ninja. No watermark, no usage limits, no credit card.

Frequently asked questions

Is Unit converter really free?
Yes — completely. PlanckUi widgets are free forever, with no watermark, no usage limits and no credit card. Paid widget platforms charge $15–40 per month for the same embeds.
Do I need an account to use Unit converter?
No. Click "Copy HTML" and paste it on your site — that's the whole flow. An account is only needed if you want to collect live data (like customer testimonials) and manage it from a workspace.
Does it work on Wix, Squarespace, Webflow, WordPress or Shopify?
Yes. If a platform lets you paste an HTML embed block — and all of them do — Unit converter works there. The snippet is plain HTML and CSS in an isolated shadow root, so it can't fight with your theme.
Will Unit converter slow down my website?
No. The widget is a few kilobytes of HTML and CSS rendered locally in your browser — no external requests, no tracking scripts, no layout shift.

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