What We Check
We don't just run a Lighthouse score and hand it to you. We test your site under real-world conditions — desktop on broadband and mobile on throttled 4G with reduced CPU — then compare the two side by side.
Desktop Performance
Full page load on a broadband connection. We measure total load time, time to interactive, number of requests, and total transfer size. This is your baseline.
Mobile Performance
Same page, but loaded on a simulated 4G connection with CPU throttling. This is how most of your visitors actually experience your site — and it's usually 3-5x slower than desktop.
Core Web Vitals
The five metrics Google actually uses for ranking: Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), First Contentful Paint (FCP), Time to First Byte (TTFB), and Total Blocking Time (TBT).
Image Optimization
WebP/AVIF adoption rate, lazy loading implementation, srcset responsive images, oversized image detection, and estimated bandwidth savings if images were properly optimized.
Carbon Footprint
Estimated CO2 per page view using the Sustainable Web Design model, green hosting verification, annual emissions projection, and comparison against the median website.
Load Time Comparison
Side-by-side desktop vs mobile results, with a clear delta showing exactly how much worse the mobile experience is. Most sites have a 2-4 second gap — some have 10+.
What You Learn
Your report shows exactly where your site loses time and what to fix first. Here are examples from real performance audits.
Mobile LCP is 6.2 seconds — Google threshold is 2.5s
Your largest contentful paint on mobile is nearly 2.5x the acceptable limit. The culprit: a 2.4 MB hero image served in JPEG format without lazy loading. Switching to WebP with srcset would cut this to under 2 seconds.
Desktop loads in 1.8s, mobile loads in 7.4s
Your desktop experience is fast, but your mobile visitors wait over 4x longer. The gap comes from unminified JavaScript (680 KB) and no critical CSS extraction. On a throttled 4G connection, this JavaScript blocks rendering for 3+ seconds.
Site produces 1.92g CO2 per visit — 3x the median
With 10,000 monthly visitors, your site generates roughly 230 kg CO2 annually. The primary driver is transfer size (4.1 MB per page). Optimizing images and enabling compression would reduce this by 60%.
Why This Matters
Over 60% of web traffic is mobile. Yet most performance testing tools default to desktop conditions — fast internet, powerful CPU, big screen. Your site might score 95 on your laptop and feel unusable on someone's phone at a coffee shop.
Google uses Core Web Vitals as a ranking signal. A slow LCP doesn't just frustrate visitors — it pushes you down in search results. Every 100 milliseconds of delay reduces conversion rates by roughly 7%. For an e-commerce site doing $100K/month, a 2-second improvement could mean $15K+ in recovered revenue annually.
Our side-by-side comparison makes the gap impossible to ignore. When stakeholders see "1.8 seconds on desktop, 7.4 seconds on mobile" next to each other, they understand the urgency immediately. The report includes specific, prioritized fixes — not generic advice like "optimize your images."
Related Features
SEO Audit
Page speed is a ranking factor. Poor performance hurts your search visibility directly.
View SEO Audit →Design Audit
Performance and design are connected. Heavy animations and unoptimized assets slow everything down.
View Design Audit →