PageSpeed audit

Summary#

The Free PageSpeed & Core Web Vitals Audit sends your URL to Google's official PageSpeed Insights API and renders the Lighthouse result in full: the four category scores, real-user field data where Google has it, every Core Web Vital, and the audits behind each score. It runs at /free-tools/pagespeed-audit with no account, on mobile or desktop.

Purpose#

Page speed is measurable, published and directly tied to whether visitors stay. Google's own Lighthouse run is the reference measurement, and the numbers it produces are the ones your stakeholders will quote back at you.

This page gives you that exact measurement without a signup, and renders it in full rather than reducing it to a single number, because a performance score is useless without the audit list that explains it.

Overview#

Your URL is passed to Google's PageSpeed Insights API, which runs Lighthouse in Google's own data center and returns the complete result. The four categories requested are Performance, Accessibility, SEO and Best Practices. The default device profile is mobile; the rendered report has device tabs so you can switch to desktop and back.

Nothing about the measurement is ours. We request it, cache it briefly, and render it. That means the numbers match what you would get from Google's own PageSpeed Insights site for the same URL and device.

Caching. A successful result is reused for six hours per URL and device profile, so repeated runs on the same page return instantly and do not consume Google's daily allowance. When Google is rate limiting or erroring, a stored result up to thirty days old is served rather than an error, so you get a slightly stale answer instead of nothing. Caching across the wider platform is covered in Result caching and freshness.

Timing. Lighthouse is slow on heavy pages. A single attempt is allowed up to 75 seconds and the whole request up to 82 seconds. If the mobile run fails quickly, a desktop run is attempted instead, because desktop Lighthouse is lighter and often completes where mobile did not.

Benefits#

• A genuine Google Lighthouse measurement, not an approximation.
• The full report, including field data, the filmstrip, per-category audit lists and the Lighthouse version used.
• Mobile and desktop from one run, switchable with a tab.
• Repeat runs within six hours are instant.
• No account, no card, no credits.

Use Cases#

• Diagnosing a slow page. The audit list names the specific blocking script or oversized image.
• Checking a release. Run before and after a deploy on the same URL and compare.
• Making the case for performance work. The category gauges and the Core Web Vitals verdict are a short, credible slide.
• Auditing a competitor. No verification is needed, so you can run it on any public page.

Requirements#

A public URL that Google can reach. Pages behind authentication, on an internal network, or blocking Google's fetch cannot be audited.

Permissions#

Anyone. No account, plan or role. A shared hourly fair-use limit applies per IP address across the free tools.

Cost#

Free. Zero credits.

Navigation Path#

metricvaultai.com → Free tools → PageSpeed Audit

The page is at /free-tools/pagespeed-audit.

Inputs#

Helper line: No signup · Powered by Google's official PageSpeed Insights API.

Step-by-Step Guide#

1. Open /free-tools/pagespeed-audit.
2. Enter the page in the field marked example.com.
3. Select Run Audit. The button reads Running… and the result area shows Running Lighthouse audit in Google's data center… (15–30s). Heavy pages take longer than that estimate.
4. Read the four gauges, then the Core Web Vitals verdict, then the Performance audits.
5. To see the other device profile, select the Desktop or Mobile tab at the top of the report. The audit re-runs for that profile.

Reading the Results#

Device tabs. Mobile and Desktop, with the audited URL shown on the right.

Discover what your real users are experiencing. Field data from the Chrome User Experience Report, described on screen as Field data over the last 28 days from the Chrome User Experience Report. This is what real Chrome visitors measured, not a lab run. It shows a Passed — Core Web Vitals Assessment or Failed — Core Web Vitals Assessment badge, and where both are available, tabs for This URL and Origin.

If Google has no field data for the page, the section says so plainly:

That is common for low-traffic pages and is not an error.

Category gauges. Performance, Accessibility, Best Practices and SEO, each 0-100, with the legend 0–49, 50–89, 90–100.

Per-category sections. Under each gauge, the audits Lighthouse ran, grouped as Google groups them, with Diagnostics collecting the rest. Performance also shows the lab metrics and the screenshot filmstrip.

Lab metrics and their thresholds.

Report footer. Captured at <timestamp>, the emulated device (Emulated Desktop or Emulated Moto G Power for mobile), the Lighthouse version and the locale. Where Lighthouse recognizes your platform it also shows a Detected: <platform> note with platform-specific guidance.

The compact fallback. Very old cached results predate the full report format. When one is served, the page falls back to a simpler render: four score cards, a Core Web Vitals grid of LCP, FCP, CLS, TBT, INP and SI, a Top Opportunities list and a Diagnostics list. The numbers are the same; only the presentation is reduced.

Examples#

Screenshots#

Tips#

• Judge the page on mobile first. It is the default profile because it is where most visitors are and where problems appear.
• Field data and lab data disagreeing is normal. Field data is what real visitors experienced over 28 days; the lab run is one measurement on one emulated device.
• Repeat runs within six hours return the cached result. Wait for the cache to expire before re-measuring a fix, or measure a different URL.
• Audit a real content page, not only the homepage. Homepages are often the most optimized page on a site.

Best Practices#

• Fix the LCP element first. It is usually a hero image or a headline, and making it load first moves the metric that carries the most weight.
• Remove render-blocking scripts and stylesheets before you optimize anything else. They delay everything downstream.
• Give images, ads and embeds explicit dimensions so late content does not push the page around. That is what brings CLS down.
• Re-test after every release. A single new tag manager script can undo a quarter of tuning.

Common Mistakes#

• Chasing 100 on Performance. It is a synthetic score. Passing Core Web Vitals in the field is the outcome that matters.
• Testing once and declaring victory. Lighthouse results vary run to run. Compare like with like and look at the field data over time.
• Assuming no field data means a problem. It usually means the page does not have enough Chrome traffic for Google to report on.
• Optimizing the homepage only. Visitors land on many pages.

Limitations#

• One URL per run, and one device profile at a time.
• The measurement is Google's. If Google cannot reach or render the page, no result is produced and there is no fallback measurement of our own.
• Results are cached for six hours per URL and device, so a fix made minutes ago may not be reflected until the cache expires.
• Very heavy pages can exceed the time budget and time out.
• The free page has no export, no scheduling and no compare view. Those toolbar actions exist in the app; see Free tools, no account needed and Exporting results.
• Nothing is saved. Close the tab and the report is gone.

Troubleshooting#

FAQs#

Is this the same as Google's PageSpeed Insights? It uses the same official API and renders the same Lighthouse result, so the numbers match for the same URL and device profile.

Why do mobile and desktop give different scores? Lighthouse throttles the CPU and network for the mobile profile to emulate a mid-range phone. Desktop runs unthrottled. Different conditions, different numbers.

What is the difference between field data and lab data? Field data comes from real Chrome users over the previous 28 days. Lab data is one controlled measurement. Field data is the truth about your visitors; lab data is what you debug against.

Why is there no field data for my page? Google only reports it where enough real Chrome traffic exists. Low-traffic pages often have none, which is not an error.

How long is a result cached? Six hours per URL and device profile. If Google is unavailable, a stored result up to thirty days old is served instead of an error.

Is it really free? Yes. No account, no card, no credits.

What does the in-app version add? PageSpeed & Vitals runs the same audit inside your workspace, where the result is saved to your history and can be exported. Whole-site performance work starts at Site Audit.