RESPONSIVE DESIGN CHECKER

Check If Your Website Is Mobile-Friendly

Run 14 mobile-friendliness checks, then run an Advanced Google Lighthouse audit for real rendered results including performance metrics.

📱14 Mobile Checks Lighthouse Advanced 📊Performance Metrics 📥CSV / TXT Export 🆓Free to Use
Understanding Mobile-Friendliness

Why Is a Mobile-Friendly Website Important?

With the majority of web traffic now coming from mobile devices, having a mobile-friendly website is essential.

User Experience First

A responsive site provides a great user experience by adapting its layout to fit any screen size, from desktops to smartphones. Users expect pages to load quickly and be easy to navigate on mobile devices.

Google's Mobile-First Indexing

Google uses mobile-first indexing, meaning it primarily uses the mobile version of your content for indexing and ranking. A non-mobile-friendly site can severely harm your SEO performance.

How This Tool Works

Basic mode checks your page's HTML source for 14 mobile-friendliness factors. Advanced mode calls Google's PageSpeed Insights API (Lighthouse) to render your page like a real mobile browser and return real metrics.

Basic vs Advanced Analysis

Basic mode = fast source-level checks (viewport, HTTPS, charset, media queries, risk detection). Advanced mode = real rendered Lighthouse audit with Performance, Accessibility, Best Practices, SEO scores and performance metrics (LCP, INP, CLS, FCP, TBT, Speed Index).

Mobile-Friendly Test

Built & maintained by Bhavin J. Sheth | Last updated on August 13, 2026

Enter the full URL including https:// to test mobile-friendliness. Max length 2048 characters.

Usage Limits: Basic checks: 30/hour per IP • Advanced Lighthouse audits: 10/hour, 30/24 hours per IP • Site-wide: 300 Advanced audits/hour. These are our safety caps to ensure fair access for all users.

Privacy note: your URL is fetched from our server for analysis but not stored after the request completes. Advanced mode sends your URL to Google's PageSpeed Insights API. A temporary rate-limit record is kept for abuse prevention.

What the Test Checks

Meaning of Each Result

Understanding what each mobile-friendliness check means.

📐

Viewport & Encoding

Checks the <meta name="viewport"> tag with width=device-width, plus character encoding so text renders correctly on mobile.

📄

Content & Meta

Checks for a page title, meta description, and HTML lang attribute — basic signals that help both users and search engines.

🎨

Responsive Design

Detects responsive CSS media queries and responsive image hints (srcset, max-width:100%) in the page source.

🚫

Plugins & Embeds

Flags outdated plugins (Flash/Silverlight) and fixed-width iframes that break on small screens.

⚠️

Risk Detection

Flags potential fixed-width elements and very small inline font sizes that commonly cause mobile problems.

Advanced Lighthouse

Optional Advanced mode runs Google Lighthouse (mobile) for real rendered checks: content width, tap targets, performance metrics, and category scores.

Honest by Design — What This Tool Does and Doesn't Do

This tool provides a preliminary mobile audit plus an optional real Lighthouse audit. Here is exactly what it does and does not do:

  • ✓ Basic mode checks 14 mobile factors instantly (most are source-level).
  • ✓ Advanced mode runs Google PageSpeed Insights (Lighthouse, mobile strategy) for real rendered results.
  • ✓ Clearly labels which checks are source-level and which require rendering.
  • ✓ Does not guarantee your site will rank better — mobile-friendliness is one factor among many.
  • ✓ Does not replace Google's official Mobile-Friendly Test for a definitive verdict.

This tool does

  • Run 14 mobile-friendliness checks (source-level + info-level)
  • Run Advanced Google Lighthouse mobile audit
  • Show Performance / Accessibility / Best Practices / SEO scores
  • Show performance metrics (LCP, INP, CLS, FCP, TBT, Speed Index)
  • Export results as CSV or TXT
  • Link to Google's official test for a final verdict

This tool does not

  • Pretend source checks are rendered checks
  • Replace Google's official Mobile-Friendly Test
  • Guarantee SEO ranking improvements
  • Store your URLs after analysis
  • Require an API key for basic checks
  • Claim a universal "mobile score" beyond Lighthouse
Why It Matters

Why Mobile Testing Matters More Than Ever

Most websites are experienced on mobile devices, so a page that works well on desktop can still create a poor experience for mobile visitors.

📱 Mobile-First Experience

Your website should remain easy to read, navigate and interact with on smaller screens — not simply shrink the desktop layout.

🔎 Search Visibility

Google uses the mobile version of a site's content for indexing and ranking, so important content and metadata should be available and usable on mobile.

⚡ Real-World Performance

Mobile devices can have slower CPUs, limited resources and variable network conditions. A page that feels fast on a desktop may feel slow on a phone.

👆 Touch & Usability

Small buttons, crowded links, horizontal scrolling and hard-to-read text can make otherwise good content frustrating to use on a touchscreen device.

📱 Mobile usability
📐 Viewport
📏 Content width
🔤 Text readability
👆 Tap targets
⚡ Performance
👁️ Content visibility

A mobile-friendly check is not only about passing a technical test. It is about making sure real users can access, understand and interact with your website comfortably.

📱

Mobile-Friendly Does Not Mean Mobile-Only

A good website should work across devices. Mobile testing deserves extra attention because Google uses the mobile version of a site's content for indexing and ranking, while mobile users may also experience different performance and usability conditions compared to desktop users.

📱

Want to Master Mobile-First Design?

We published a complete guide explaining mobile-first indexing, responsive design principles, viewport configuration, tap target best practices, font size recommendations, and how to create websites that work beautifully on all devices.

📘 Read Full Mobile Design Guide →

Written by Bhavin Sheth

Quick Guide

How to Use This Mobile-Friendly Test

Four steps from entering a URL to a full mobile audit.

1

Enter Your URL

Type the full URL (including https://) of the webpage you want to test.

2

Run the Basic Test

Get 14 mobile-friendliness checks with Pass / Fail / Info statuses.

3

Run the Advanced Audit

Click "Run Advanced Mobile Audit" to get real Google Lighthouse scores and performance metrics.

4

Verify with Google

Use the provided link to run Google's official Mobile-Friendly Test for a final verdict.

Troubleshooting Guide

Common Mobile-Friendliness Issues and What They Mean

If your page fails the test, check these common causes.

📐

Missing Viewport Tag

FAIL

No <meta name="viewport"> tag found.

Solution: Add <meta name="viewport" content="width=device-width, initial-scale=1"> to your HTML <head>.

🔤

Small Inline Fonts

RISK

Inline font sizes below 12px detected.

Solution: Use a base font size of at least 16px and relative units (rem, em) for better scaling.

📏

Fixed-Width Elements

RISK

Potential fixed-width elements (≥700px) detected.

Solution: Use responsive images with max-width:100% and avoid fixed-width containers.

🚫

Incompatible Plugins

FAIL

Flash or other outdated plugins detected.

Solution: Remove Flash/Silverlight. Use HTML5, CSS3, and JavaScript for interactive content.

🖼️

Non-Responsive Images

INFO

Images found but no responsive hints detected.

Solution: Add srcset/sizes or CSS max-width:100% to images.

🔒

Could Not Fetch URL

FETCH FAILED

The tool couldn't access your URL.

Solution: Check that the URL is public and accessible. If the site blocks crawlers, the tool cannot analyze it.

Decision Guide

When to Use This Mobile-Friendly Test

Use the test for these common scenarios.

When you use it
What the test reveals
What to do next
Before launching a new site
Whether your site meets basic mobile-friendliness requirements.
Fix failed checks, then run the Advanced audit and Google's official test.
SEO audit
Mobile usability issues that could harm search visibility.
Prioritize viewport and tap-target issues. Mobile usability is one part of overall SEO.
After a redesign
Whether the new design maintains mobile-friendliness.
Verify all pages pass and test on real devices for real-world validation.
Performance review
Performance metrics and Lighthouse category scores (Advanced).
Address LCP/CLS/TBT issues using the specific audit recommendations.
Client reporting
Mobile-friendliness status for stakeholder reports.
Export CSV/TXT and include in monthly SEO reports.
Troubleshooting traffic drops
Whether mobile usability issues are causing traffic loss.
Cross-check with Google Search Console's Mobile Usability report.
Frequently Asked Questions

Mobile-Friendly Test FAQs

Answers based strictly on what this tool does and how mobile-friendliness works.

?

Why is my site "Likely NOT Mobile-Friendly"?

The most common reason is a missing <meta name="viewport"> tag. Other factors include content wider than the screen, fixed-width elements, or font sizes that are too small.

?

What's the difference between Basic and Advanced?

Basic mode runs 14 mobile checks against your page source (13 source-level + 1 info). Advanced mode calls Google's PageSpeed Insights API, which renders your page like a real mobile browser and returns Lighthouse scores plus performance metrics.

?

Why do some checks show "Info"?

Some checks (actual tap-target size, rendered content width) require full browser rendering. Basic mode flags these as "Info" rather than pretending to pass or fail them. Run the Advanced audit for rendered results.

?

What are "tap targets"?

Tap targets are elements users tap: buttons, links, form fields. If too small or too close together, they're hard to press accurately on touchscreens, leading to a poor experience.

?

Why are there usage limits?

To ensure fair access for all users: Basic checks are limited to 30/hour per IP, Advanced Lighthouse audits to 10/hour and 30/24 hours per IP, and 300 Advanced audits/hour site-wide. These caps protect our Google API quota and prevent abuse.

?

Does mobile-friendliness affect SEO?

Yes. Google uses mobile-first indexing. Sites with poor mobile usability may rank lower than mobile-friendly competitors, all else being equal — but it is one factor among many.

?

Why is the font-size check sometimes "Info"?

Newer Lighthouse versions removed the old legible-font-size audit. When it's unavailable, we report "Info" instead of a fake Pass/Fail. Basic mode still flags very small inline font sizes as a risk.

?

Is my URL stored?

No. We fetch your page for analysis but don't store the URL after the request. Advanced mode sends your URL to Google's API to run the audit. A temporary rate-limit record is kept for abuse prevention.