Free tools for your website

Add a carbon footprint calculator to your website

Help your visitors turn everyday activity into a clearer carbon footprint. Embed Sustrax Vita for individuals and households, or Sustrax Lite for organisations, using the ready-to-copy HTML below.

Get the embed code ↓Explore the affiliate programme

Two free calculatorsResponsive widthAutomatic height adjustment

Choose your audience

Your website. Their first step.

Each snippet includes the styling, calculator iframe and resizing script. Use either one on its own, or add both to the same page.

Individuals & households

Sustrax Vita

Give your community a practical way to explore emissions from home energy and travel.

Try the personal calculator →

View Vita embed code HTML + CSS + JavaScript

<style>
    #sustrax_vita_iframe {
    box-sizing: border-box;
    border: 10px solid #f0f0f0;
    border-radius: 25px;
    width: 100%;
    min-height: 100vh;
    overflow: hidden;
    }
</style>
<iframe id="sustrax_vita_iframe" title="Sustrax Vita personal carbon calculator" src="https://iframe.app.sustrax.com/dashboard" scrolling="no"></iframe>
<script>
    window.addEventListener("message", function (event) {
        const iframe = document.getElementById("sustrax_vita_iframe");
        if (event.data && event.data.height && event.source === iframe.contentWindow) {
            const newHeight = event.data.height + 400;
            if (newHeight > 1200) iframe.style.height = newHeight + "px";
        }
    }, false);
</script>

Organisations & small businesses

Sustrax Lite

Let business visitors register or log in to start their annual carbon footprint with a free Lite account.

Explore the business calculator →

View Lite embed code HTML + CSS + JavaScript

<style>
    #sustrax_lite_iframe {
    box-sizing: border-box;
    border: 10px solid transparent;
    width: 100%;
    overflow: hidden;
    min-height: 700px;
    }
</style>
<iframe id="sustrax_lite_iframe" title="Sustrax Lite log-in and registration" src="https://app.sustrax.com/login"></iframe>
<script>
    window.addEventListener("message", function (event) {
        const iframe = document.getElementById("sustrax_lite_iframe");
        if (event.data && event.data.height && event.source === iframe.contentWindow) {
            let newHeight = event.data.height + 100;
            if (newHeight < 800) newHeight = 800;
            iframe.style.height = newHeight + "px";
        }
    }, false);
</script>

Lite Free has plan limits; paid upgrades are available. Compare business plans. For team reporting, start a free Sustrax MX trial.

From code to calculator

Set up in three steps

01
Copy your snippet
Choose Vita or Lite above and copy the complete block, including the style and script tags.
02
Paste into your page
Use your page’s HTML editor or a custom HTML block that permits iframes and scripts. Your web developer can help if your CMS restricts these.
03
Preview and check
Open the published page on desktop and mobile. Step through the calculator and check that the frame resizes. For Lite, also check registration and login.

Give visitors a short introduction explaining who the calculator is for and what information they will need. Get help with setup.

Affiliate & partner programme

Help your clients.
Grow your offering.

Work with Carbon Footprint Ltd through its partner programme. Both pathways earn commission on Sustrax and carbon credit deals and include expert support on demand for your clients.

Recommend & refer

Referral Partner

Free to join. Introduce your network to Carbon Footprint Ltd’s tools and services and earn referral commission, while Carbon Footprint Ltd handles delivery of the software.

Apply as a referral partner →

Build your service

Certified Reseller

A paid partner package with a Sustrax MX licence for your business, autonomy on client projects, and access to the partner dashboard and toolkit.

Compare the reseller package →

Embedding a calculator does not enrol you as a partner or add referral tracking. Talk to the team about eligibility, commission terms and opportunities with the Carbon Offset Marketplace (COMP).

A little help with setup

Embedding questions, answered

Is it free to add a Sustrax calculator to my website?

You can use the supplied embed code for the free Vita calculator and the Lite login and registration page. Lite users can start on Lite Free; additional capabilities require a paid plan. See the current plan comparison.

Can I embed both calculators on the same page?

Yes. The Vita and Lite snippets use different iframe IDs and work independently. Paste each complete snippet once. They can also sit on separate pages.

Can I use this with WordPress or another website builder?

Use a custom HTML block or template area that allows style, iframe and script tags. Some editors, account permissions or site settings remove scripts. If that happens, ask your web developer to place the complete snippet in a supported template area.

Why is the calculator blank or not resizing?

Check that the complete code remains in the published HTML and that your site allows the calculator’s iframe domain and resizing script. Test on the published page as well as in the editor. Browser privacy settings can also affect embedded login. Give visitors a direct link to open Vita or open Lite if they have difficulty.

Will an embedded carbon calculator help my website’s SEO?

A useful calculator can give visitors a reason to use and share your page. Add your own relevant introduction, preparation guidance and practical next steps in the page’s HTML. Google may associate iframe content with its parent page, but this is not guaranteed and an embed does not guarantee a ranking improvement. Read Google’s explanation of iframe indexing.

Does the embed include affiliate tracking?

These are standard calculator snippets. They do not include an affiliate ID. Contact the team to arrange a partnership and confirm referral tracking separately. Where you add paid or affiliate links, use the appropriate rel="sponsored" link attribute, following Google’s guidance for commercial links.

Need carbon accounting for your whole organisation?

Explore Sustrax MX for monthly tracking, multi-site data collection and team reporting.

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