Website Carbon Footprint Calculator
Check your website's carbon, speed scores, and digital waste in 60 seconds. Powered by the EcoPigs P.E.E.R. engine with live grid carbon data.
Check Your Website's Carbon Footprint
Instant analysis across emissions, performance, experience, and ranking.
How It Works
Our tool goes beyond a simple carbon number. It scores your site across four areas using the P.E.E.R. framework.
The Sustainable Web Design (SWD) Model
We use the Sustainable Web Design (SWD) model, the most common method for website carbon. It works out CO2 from data sent, the energy used by data centres and networks, and how dirty the power grid is. Unlike basic tools, ours pulls in live grid data, so your result matches the real carbon picture at scan time.
Live Grid Carbon Intensity Data
A website's carbon changes based on when and where it loads, because power grids vary in how clean they are. A page loaded at noon in Scotland (lots of wind power) emits less than the same page at 6pm in London (more gas). Our tool uses live UK National Grid data to factor this in.
What Your Score Means
Your P.E.E.R. score has four parts: Performance (speed), Experience (access and ease of use), Emissions (carbon and waste), and Ranking (SEO and search reach). Each is graded F to A+. The total weights them: Performance 25%, Experience 20%, Emissions 30%, Ranking 25%.
Why Measure Your Website's Carbon Footprint?
Scope 3 Reporting
Digital systems fall under Scope 3. With CSRD and UK green rules growing, having hard data on your digital carbon gives you audit-ready proof.
Regulatory Pressure
The EU's CSRD and the UK's new green rules now push more firms to report on their impact, including digital. Start measuring early to build a baseline.
Performance Correlation
Lower carbon means less data sent, which means faster loads. Cutting your footprint directly boosts UX, sales, and search rank.
What to Do With Your Results
Quick Wins for Any Website
- Compress and resize images — Switch to WebP and serve at the right size. This alone often cuts 40-60% of page weight.
- Audit third-party scripts — Remove tracking, chat tools, and pixels you do not use. Each one adds weight and requests.
- Enable caching — Set strong cache headers on static files. Return visitors should download almost nothing.
- Defer extra JavaScript — If it does not affect the first paint, load it later.
- Tune font loading — Load one weight first, defer the rest. Use
font-display: swapto stop blank text while fonts load.
When You Need a Full Audit
The free scan checks your homepage. If you score below B, or need full-site data, a P.E.E.R. Digital Waste Audit covers every page. You get access checks, waste breakdowns, a ranked action plan, and ROI forecasts. If you need to report on digital carbon, the audit gives you the docs for Scope 3 reporting.
Frequently Asked Questions
Is this calculator free?
Yes, fully free. Enter any URL and get an instant look at your site's carbon, speed scores, and waste breakdown. No card needed.
How accurate is it?
It uses the Sustainable Web Design (SWD) model, the most common method for website carbon. It gives a useful, repeatable estimate. Like all models, it works best for tracking progress over time, not as an exact measure.
What is a good score?
A good website produces less than 0.5g CO2 per page view. The average UK website produces 1.0-2.0g. Well-optimised sites achieve under 0.1g. The overall P.E.E.R. grade of A or above indicates strong performance across emissions, speed, accessibility, and SEO.
How does this compare to Website Carbon Calculator?
This tool goes beyond basic carbon estimation. While Website Carbon Calculator provides a single CO2 figure, our tool also analyses performance metrics (LCP, CLS, TTFB), breaks down digital waste by category, provides prioritised quick wins, and scores across four dimensions using the P.E.E.R. framework.
Ready for the Full Picture?
The free scan is a starting point. A full P.E.E.R. audit covers every page on your site with detailed analysis, compliance documentation, and a prioritised roadmap.