What are Core Web Vitals?

Core Web Vitals are three metrics Google uses to measure user experience: LCP (how fast the main content loads, target under 2.5s), FID (how quickly the page responds to input, target under 100ms), and CLS (how much the layout shifts during loading, target under 0.1). These directly affect your Google search ranking.

Why are mobile and desktop scores different?

Mobile analysis simulates a mid-range phone on a slow 4G connection, while desktop uses a high-speed desktop environment. Mobile scores are typically lower because the simulated conditions are more constrained. Google uses mobile-first indexing, so the mobile score matters more for rankings.

What is a good Performance score?

90-100 is good (green), 50-89 needs improvement (yellow), and 0-49 is poor (red). Most websites score 30-70 on mobile. Focus on the specific CWV metrics rather than just the overall score.

How is this different from other speed tests?

This tool uses the official Google PageSpeed Insights API — the same data Google uses for ranking decisions. Other tools may measure from their own servers with different methodologies. We also show basic server response time alongside Lighthouse data for a complete picture.

Security & Network

Website Speed Test

Test any website with Google PageSpeed Insights — Lighthouse scores, Core Web Vitals (LCP, FID, CLS), mobile vs desktop, plus basic load metrics.

100% free
No sign-up
Clear controls
Open and use

What this tool does

Google PageSpeed Insights integration
Core Web Vitals: LCP, FID, CLS, FCP, TTFB
Lighthouse scores: Performance, Accessibility, SEO
Mobile vs Desktop toggle
Basic load time + page size
Actionable speed tips

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The short version

What is Website Speed Test?

A website speed test measures how fast a website loads and provides actionable performance data.

This tool integrates Google PageSpeed Insights to give you Lighthouse scores for Performance, Accessibility, Best Practices, and SEO, plus Core Web Vitals measurements including LCP (Largest Contentful Paint), FID (First Input Delay), CLS (Cumulative Layout Shift), FCP, TTFB, and TBT. Toggle between mobile and desktop analysis to see how your page performs on different devices. Google uses these metrics as ranking signals, so optimizing them directly improves your search visibility.

Website Speed Test showing a worked example — Test any website's loading speed — TTFB, total load time, page size and request count. — Website Speed Test with the built-in example loaded. Free, no sign-up, and the result appears as you type.

Step by step

How to use Website Speed Test

1
Enter a URL
Type any website URL. HTTPS is added automatically if omitted.
2
Click Test
We run Google PageSpeed Insights and measure basic load metrics simultaneously. Analysis takes 15-30 seconds.
3
Toggle Mobile/Desktop
Switch between mobile and desktop to see Lighthouse scores and Core Web Vitals for each device type.
4
Review CWV and follow tips
Core Web Vitals are color-coded: green (good), yellow (needs work), red (poor). Follow the speed tips for actionable improvements.

What's inside

Everything this tool
does for you

Google PageSpeed Insights API integration
Lighthouse scores: Performance, Accessibility, Best Practices, SEO
Core Web Vitals: LCP, FID, CLS, FCP, TTFB, TBT, SI, INP
Mobile vs Desktop toggle
Color-coded CWV thresholds (Good / Needs Work / Poor)
Basic load time, page size, and resource counts
Compression and caching detection
Actionable speed optimization tips

Understand the result

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Questions

Frequently asked questions

Beyond this tool

See the full picture for your website.

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What is Website Speed Test?

How to use Website Speed Test

Enter a URL

Click Test

Toggle Mobile/Desktop

Review CWV and follow tips

Everything this tooldoes for you

Further reading

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Frequently asked questions

What are Core Web Vitals?

Why are mobile and desktop scores different?

What is a good Performance score?

How is this different from other speed tests?

See the full picture for your website.

Everything this tool
does for you