UK Small Business Carbon Study
Original research: we audited 100 real UK small-business homepages for carbon across 18 sectors, published the findings, and released the full dataset under an open licence.
Most writing about sustainable web design leans on the same handful of global statistics. We wanted UK-specific numbers for the businesses we actually work with — the plumbers, cafés, solicitors and salons that make up most of the British web. Nobody had published them, so we did.
The Question
How heavy, and how carbon-hungry, is the ordinary UK small-business website in 2026 — and where does the weight actually come from?
The Method
We built the sample the way a customer would find these businesses: searching “plumber Preston”, “florist York”, “dentist Exeter” and taking the independent firms that appeared — no directories, no aggregators, no national chains. That gave us 100 businesses across 18 sectors, from Exeter to Edinburgh.
Every homepage went through the same crawler that powers our free Website Carbon Audit: a first-visit measurement that respects lazy-loading and srcset, with emissions estimated via co2.js v4 (the Sustainable Web Design Model) and hosting checked against The Green Web Foundation’s verified directory. 99 of the 100 sites audited successfully.
What We Found
- The median homepage weighs 1.8 MB across 46 requests — and the mean is 3.0 MB, dragged up by a heavy tail. The heaviest page we measured was 22.6 MB; the lightest was 19 KB, doing broadly the same job.
- 44% of sites rate E or F on the digital carbon scale. Only 18% manage an A or A+.
- Images are 60% of every byte transferred — usually full-resolution photographs scaled down in the browser. Fonts were the quiet second offender.
- Green hosting is largely accidental. 63% of sites pass a verified green hosting check, but over half of those passes are just a CDN being detected. Only one site in four pairs green infrastructure with a genuinely efficient page.
The full analysis — including a sector league table topped by landscapers and won, at the efficient end, by MOT garages — is in the write-up: We Audited 100 UK Small Business Websites for Carbon.
The Dataset
We released the whole thing. Anonymised per-site measurements — transfer bytes, request counts, per-asset-type breakdowns, hosting status, CO₂e per view and rating — are published under CC BY 4.0 as CSV and JSON aggregates, with schema.org Dataset markup so researchers can find it. If you use it, we’d love to hear what you build.
Why It Matters to Clients
This study is what our environmental consultancy looks like in practice: measure first, then advise. The same numbers now anchor how we scope web projects — most sites in the sample could halve their footprint in a focused afternoon, and the fixes that cut carbon are the same ones that cut load time.