Free to use, no attribution fee, no sign-up
Put this calculator on your site.
One line of HTML. It sets no cookies, loads no scripts onto your page, and sends nothing anywhere — so it will not touch your privacy policy or your Core Web Vitals.
What your visitors get
Live demo — this is exactly what appears on your page. Try typing 12'6" or 366cm.
The embed code
Paste this wherever you want the calculator to appear. It works in WordPress (a Custom HTML block), Squarespace, Wix, Ghost, Webflow, plain HTML, and anything else that accepts an iframe.
<iframe src="https://sqftcalc.com/embed"
width="100%" height="400" frameborder="0"
title="Square Footage Calculator"
loading="lazy" style="border:0;max-width:660px"></iframe>
<p style="font:13px system-ui,sans-serif">
<a href="https://sqftcalc.com/">Square Footage Calculator</a> by SqFtCalc
</p>
Keep the credit line below the iframe. That is the only thing we ask in return, and it is what pays for the widget being free.
Why this one is safe to embed
No cookies, at all
Not first-party, not third-party, not local storage. It cannot affect your cookie banner or your GDPR position, because there is nothing to disclose.
No JavaScript on your page
Everything runs inside the iframe. Nothing touches your own scripts, and nothing can slow down or break the rest of your page.
No data leaves the browser
Measurements are calculated on the visitor's device and never sent anywhere. Open the network tab and watch: after it loads, it makes no requests.
Light and lazy
About 14 KB, no webfonts, and loading="lazy" means it costs nothing until a visitor scrolls to it.
If you want it to resize itself
The fixed height above works fine on every screen size we test. If you would rather it grow and shrink to fit its content exactly, add this small script — it listens for a height message from the iframe and does nothing else.
<script>
window.addEventListener("message", function (e) {
if (e.origin !== "https://sqftcalc.com") return;
if (!e.data || e.data.sqftcalc !== "height") return;
var f = document.querySelector('iframe[src^="https://sqftcalc.com/embed"]');
if (f) f.style.height = e.data.height + "px";
});
</script>
The origin check is deliberate. It means the snippet ignores messages from anything other than us, so adding it cannot open a hole in your page.
Terms, in full
You may:
- Embed it on any site, personal or commercial, including sites that run ads.
- Embed it on as many pages and as many sites as you like.
- Set your own width, and place it anywhere on the page.
Please don't:
- Remove the credit link, or mark it nofollow.
- Copy the calculator's code and host it yourself — embed it instead, so you get the fixes.
- Present it as your own tool.
We may change or improve the widget, and improvements appear on your page automatically. If we ever needed to retire it we would leave a working version in place rather than break your page. Estimates are estimates — the same terms apply as on the rest of the site.
Questions
Does it cost anything?
No, and there is no paid tier. The credit link is the price.
Will it slow my page down?
It is about 14 KB with no webfonts and no external requests, and the snippet sets loading="lazy" so nothing loads until a visitor scrolls near it. It cannot block your render, because an iframe never does.
Do I need to mention it in my cookie policy?
There is nothing to mention. The widget sets no cookies and uses no browser storage of any kind. We are not lawyers and your own counsel has the final say, but there is no data being collected to disclose.
Can I change the colours or the size?
Width, yes — set it to whatever suits your layout. Colours are fixed for now, deliberately, so that every embed stays recognisable and so we can fix a rendering bug everywhere at once. If you have a specific need, get in touch.
What happens if you take it down?
We would leave a working version at that URL rather than break pages that trusted us. That said, an iframe is a dependency on somebody else's site, and you should weigh that the same way you would any embed.