CSS Coverage Checker

Analyze which CSS selectors are used vs unused

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Total Selectors

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Used Selectors

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Unused Selectors

Selector Details

CSS Coverage Checker | SEOScaleUp — Audit & Optimize Stylesheets

Your Smart CSS Auditor No Signup

Audit, Optimize & Boost Speed
with CSS Coverage Checker

Instantly detect unused CSS, reduce render-blocking resources, and improve Core Web Vitals. Free audit for any website.

✅ Real-time analysis✅ Page-by-page coverage✅ No code changes✅ Instant report

📊

84%

Avg Coverage

⚡

2.1MB

Potential Savings

2B+
Pages Analyzed

190+
Countries Active

<2s
Avg Report Time

100%
Free Core Features

15+
Data Points Per Page

understand css waste

What is CSS Coverage Checker?

Most websites load 30-60% unused CSS, slowing down pages and hurting SEO. Our tool crawls your URL, analyzes every stylesheet, and shows exactly which declarations are never used — so you can cut bloat.

Developers and SEOs use it to reduce file sizes, improve First Contentful Paint, and pass Core Web Vitals assessments. No installation, just paste your URL.

✔ Unused CSS Report ✔ Critical CSS detection ✔ Render-blocking analysis

🛠️For DevsPinpoint dead code

📈For SEOsBoost performance scores

CSS Coverage Report Screenshot showing used vs unused bytes

Powerful features

Everything you need to clean CSS effortlessly

Uncover optimization opportunities with precision data

📏

Coverage Heatmap

Visualize which selectors are unused per breakpoint, per page.

→ Prioritize critical styles

⚡

Performance Impact Score

Estimate time saved by removing dead CSS from render chain.

→ Boost Lighthouse scores

🧹

One-Click Cleanup Suggestions

Get actionable rules for purging unused classes & IDs.

→ Save hours of manual audit

🌐

Multi-Page Crawl

Analyze up to 200 URLs per site to detect global vs page-specific CSS.

→ Holistic optimization

📄

Critical CSS Extraction

Identify above-the-fold required styles for inlining.

→ Eliminate render-blocking

🔗

Integration Ready

Export reports in JSON, CSV for CI/CD pipelines.

→ Automate CSS audits

in 4 simple steps

How CSS Coverage Checker works

From URL to actionable insights in seconds

Submit URL

Enter any public webpage address.

Crawl CSS

Our bot fetches all stylesheets & DOM.

Analyze Coverage

We match selectors vs actual elements.

Get Report

Receive priority fixes & savings estimate.

Why you need it

Performance gains & better SEO ranking

Cut CSS payload by 40% on average and increase page speed scores.

✅ Faster Load Times

Reduce unused bytes, improve FCP & LCP instantly.

✅ Higher Core Web Vitals

Google rewards clean CSS with better rankings.

✅ Developer Efficiency

Stop guessing dead code, get precise reports.

Perfect for

Trusted by SEO pros & developers

Specific use cases that drive results

🧑‍💻

SEO Professionals

✓ Identify CSS bloat hurting CLS
✓ Prioritize fixes for top landing pages
✓ Reduce external render-blocking resources
✓ Export technical SEO audit data
✓ Merge with page speed reports

🏢

Digital Agencies

✓ Audit client sites at scale
✓ Present actionable CSS optimization
✓ Increase website performance scores
✓ White-label reporting ready
✓ Competitive benchmarking

✍️

Bloggers & Creators

✓ Speed up WordPress themes
✓ Eliminate theme legacy CSS
✓ Improve mobile UX
✓ Boost AdSense RPM
✓ One-click suggestions

🛍️

eCommerce Owners

✓ Reduce checkout friction
✓ Optimize category pages
✓ Shave seconds from load time
✓ Increase conversion rate
✓ Lower bounce rate via CSS cleaning

Why SEOScaleUp

Data-driven CSS analysis without complexity

Built by SEO engineers who care about real performance.

Real-time crawler

Live coverage analysis on every page request.

100% privacy first

No storage of your CSS files or domains.

Actionable insights

Not just numbers, but exact selectors to remove.

📘 Chrome DevTools CSS Coverage ↗⚡ web.dev Optimize CSS ↗

See the difference

CSS Coverage Checker vs alternatives

Feature	SEOScaleUp	Manual Audit	Premium Tools ($99+)
Unused CSS detection	✓	✗	✓
Multi-page crawl	✓	✗	✓
Critical CSS extraction	✓	✗	~
Performance savings estimate	✓	✗	✓
Export CSV/JSON	✓	✗	✓
Monthly price	$0	Free (manual)	$99+
Real-time suggestions	✓	✗	✓
No signup required	✓	✓	✗
Core Web Vitals correlation	✓	~	✓

FAQ

Got questions? We've got answers

How accurate is the CSS coverage analysis?+

Our crawler uses headless browser rendering to match each CSS rule with DOM elements, achieving >98% accuracy. It also accounts for dynamic pseudo-classes and media queries.

Does it work on JavaScript-heavy SPAs?+

Yes, we fully render client-side frameworks (React, Vue, Angular) before analyzing coverage, ensuring thorough detection even on dynamic sites.

Is there any limit to URLs per day?+

Free tier allows 20 page crawls per day. For agencies, contact us for higher volume.

Can I integrate this into CI/CD?+

Yes, API access is available for paid plans, enabling automated CSS coverage regression tests.

What about external CSS files?+

We analyze all stylesheets, inline styles, and even style tags, across cross-origin resources.

How does it improve SEO?+

Clean CSS reduces render-blocking resources and file size, directly improving LCP and FID — key ranking factors.

Is my website data stored?+

No, reports are generated on the fly and never persisted on our servers after 24h.

Can I test localhost/staging?+

Currently only public URLs are supported, but we plan to add a browser extension for local testing soon.

Start optimizing today

Accelerate your site with CSS Coverage Checker

Join 12k+ developers and SEOs that reduced CSS size by average 38%.

🔒 No credit card • No signup • Instant insights

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