website performance audit

Website Performance Audit — Fix Speed Issues That Kill Rankings

Google ranks faster sites higher. Users abandon slow sites in seconds. AuditAI measures your Core Web Vitals and page speed metrics, then gives you specific fixes — not just scores.

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Core Web Vitals Explained

Google's official ranking signals for page experience. These three metrics determine whether your site provides a good user experience — and whether Google rewards it in search rankings.

Largest Contentful Paint (LCP)

Good: < 2.5sNeeds work: 2.5–4sPoor: > 4s

Measures how long it takes for the largest visible element (usually a hero image or heading) to appear. The most important single metric for perceived load speed.

Common fixes:

Serve images via CDNUse WebP/AVIF formatsPreload the hero imageEliminate render-blocking resources

Interaction to Next Paint (INP)

Good: < 200msNeeds work: 200–500msPoor: > 500ms

Replaced FID in 2024. Measures the delay between user interaction (click, tap, key press) and the browser's next render. High INP means your UI feels sluggish.

Common fixes:

Break up long JavaScript tasksDefer non-critical scriptsUse web workers for heavy computationReduce third-party script impact

Cumulative Layout Shift (CLS)

Good: < 0.1Needs work: 0.1–0.25Poor: > 0.25

Measures unexpected layout shifts — elements moving around as the page loads. High CLS causes accidental clicks and a jarring user experience.

Common fixes:

Set explicit width/height on imagesReserve space for ad slotsUse font-display: optionalAvoid inserting content above existing DOM

All Metrics We Measure

Beyond Core Web Vitals, AuditAI checks six additional performance signals to give you a complete picture.

Time to First Byte (TTFB)

How fast your server responds to a request. Over 800ms suggests slow hosting, no CDN, or heavy server-side rendering.

Total Blocking Time (TBT)

Total time during which the main thread is blocked from responding to user input. High TBT usually means too much JavaScript.

Total page size

Sum of all resources. Under 1MB is ideal for mobile. Common bloat sources: unoptimized images, unused CSS, large JavaScript bundles.

Number of HTTP requests

Each request adds latency. Modern HTTP/2 handles many requests in parallel, but 100+ requests still hurt performance on slow connections.

Render-blocking resources

CSS and JS in <head> that the browser must download and parse before rendering the page. Should be zero for above-the-fold content.

Image optimization

Checks if images are appropriately sized, compressed, and using modern formats (WebP, AVIF). Unoptimized images are the #1 cause of slow LCP.

Performance Impact on SEO Rankings

Google's Page Experience update (2021) made Core Web Vitals an official ranking factor. Sites that pass the Core Web Vitals assessment (all three metrics in the "Good" range) get a small but measurable ranking boost compared to equivalent sites that don't.

More importantly, slow sites have dramatically higher bounce rates. A 3-second mobile load time has a 53% bounce rate according to Google data. High bounce rate is a negative ranking signal. Speed and SEO are inseparable.

For e-commerce sites, Walmart found that every 1-second improvement in load time increased conversions by 2%. For SaaS landing pages, faster load times improve ad Quality Score, reducing CPC on Google Ads.

53%

of mobile users leave if load time exceeds 3 seconds

2021

Year Google made Core Web Vitals a ranking signal

20%

conversion drop for every 1s of mobile load delay

Frequently Asked Questions

What are Core Web Vitals?+

Core Web Vitals are three metrics Google uses as ranking signals: Largest Contentful Paint (LCP) measures loading performance, First Input Delay (FID) / Interaction to Next Paint (INP) measures interactivity, and Cumulative Layout Shift (CLS) measures visual stability. Google officially uses these in its search ranking algorithm since 2021.

How does page speed affect SEO rankings?+

Google has used page speed as a ranking factor since 2010 for desktop and 2018 for mobile. Since 2021, Core Web Vitals specifically are a ranking signal through Google's 'Page Experience' update. Slow sites rank lower, and users bounce faster — a 1-second delay in mobile load time reduces conversions by up to 20%.

What is a good LCP score?+

Google considers LCP 'Good' if it's under 2.5 seconds, 'Needs Improvement' between 2.5–4 seconds, and 'Poor' if over 4 seconds. For most business websites, LCP under 2 seconds is achievable with image optimization and a good CDN.

What is CLS and why does it matter?+

CLS (Cumulative Layout Shift) measures how much page elements unexpectedly move while the page loads. A high CLS score means users click the wrong button because content shifted. Google considers CLS under 0.1 as Good. Common causes are images without explicit dimensions, web fonts loading late, and ads injecting content above existing text.

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