Why your digital sustainability score matters and what to do about it

Digital sustainability is no longer a niche concern—it affects the bottom line, the environment, and every team's priorities. 

As Deloitte tells us, 50% of CxOs have already begun implementing technology solutions to help achieve climate or environmental goals, with another 42% expecting to undertake this work in the next two years!

So, with digital sustainability gaining momentum across leadership roles, how and why should you get started?

Websites use energy just by existing.

It is becoming increasingly known that sustainably built websites burn significantly less carbon, cost less, and perform much better for users.

Making your site more sustainable makes it faster, more SEO-friendly, and often cheaper. If you're trying to improve performance, conversion rates, or your ESG reporting, sustainability can help.

When we reduce file sizes, remove bloated scripts, and audit what needs to load, we're not just cutting carbon—we're:

• Increasing load speed
• Boosting SEO scores
• Improving accessibility
• Reducing infrastructure costs
• Enhancing UX

Sustainable websites drive performance in more ways than one.

To give digital leaders a good starting point, my team and I at Cogworks have built an advanced Website Carbon Calculator, sporting the trusted industry Green Web Foundation framework.

The calculator shows where your website is failing and how to fix it. 

For digital leads managing performance, ESG reporting, or technical budgets, this calculator is designed to give you a roadmap to success.

There are some amazing calculators out there, but have you ever wondered why you get different results if you try a few different calculators? This is likely down to the varied methodologies. 

Here's what causes the variation:

• Some use server average instead of checking live load
• Some assume your hosting is green 
• Some skip-checking for things like third-party scripts and background video (a major contributor to non-sustainable websites)

Our senior designers, QA, and developers helped shape this calculator using a trusted, leading open-source framework. It gives users a pragmatic, evidence-based breakdown of all the performance and environmental bottlenecks contributing to your website's sustainability.

If you want to learn exactly how this is measured, head to the methodology page. 👇

CO₂.js is a trusted, open-source JavaScript library used by sustainability-conscious platforms like Ecograder from Mightybytes and many more.

CO₂.js gives us a solid, science-backed baseline. It's transparent, peer-reviewed, and constantly evolving. 

But we wanted to give more to digital leaders who need data they can explain, defend, and act on. So we've layered in:

• Verified hosting lookups using the Green Web Foundation's database

• Asset-level performance inspection using Lighthouse to ensure we're accounting for real transfer, not just estimates

• Regular methodology updates so your results stay meaningful as infrastructure, standards, and energy grids change

• Insights on what to do next

Have you run the calculator and seen your score?

Did it surprise you?

If you're surprised (and not in the best way🫠), there might be a few quick wins you can do:

• Optimise images
• Remove unnecessary code
• Switch to green hosting
• Check or limit third-party scripts
• Track, track and track again using a Website Carbon Calculator tool

You don't need a task force to begin. You can start small.

Just grab your website URL and dive in:

👉 Check your website's carbon score for free

For a complete list of quick-win actions, check out the Digital Sustainability Playbook.

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If you have any questions or feedback about the calculator, please don't hesitate to contact our digital sustainability team.