# Lighthouse alternatives for measuring page speed

Lighthouse is a lab tool: one simulated load on a mid-range phone over a throttled connection, scored out of 100. That is useful for finding causes and useless as a verdict, because Google judges page experience on what real Chrome users experienced. The alternatives split into tools that show you field data, tools that go deeper into one load, and tools that watch a page over time. This page says which to open for which question.

Updated 2026-09-15 · Source: https://porteur.ai/alternatives/lighthouse-alternatives

## Why people look past Lighthouse

Three complaints, and all three are correct.

- The score moves between runs of the same page, because a simulated load is not deterministic. A performance score is a reading, not a fact.
- It is lab data. Google's page experience assessment uses field data: the 75th percentile of real Chrome users' loads over 28 days, per URL or per origin.
- It cannot interact with the page, so it cannot measure Interaction to Next Paint, which replaced First Input Delay as a Core Web Vital in March 2024. It reports Total Blocking Time as a lab proxy instead.

> The Lighthouse performance score weights Total Blocking Time 30%, Largest Contentful Paint 25%, Cumulative Layout Shift 25%, First Contentful Paint 10% and Speed Index 10%. A score can fall because of a metric that does not affect your visitors' experience of the page.

## The criteria that decide it

- Lab or field: a simulated load, or what your real visitors experienced.
- One page or the whole site: a single URL, or every URL grouped.
- Depth: a verdict, or the request-by-request evidence.
- Watching: a run you trigger, or a schedule with alerts.
- Interaction: can it measure what happens after a click.

## The alternatives, by what you need

1. **The verdict, free: PageSpeed Insights** It runs Lighthouse and shows the Chrome User Experience Report field data above it, so one page gives you both the judgement and the diagnosis. Read the field section first; the lab score below it is the explanation, not the grade.
2. **Field data at scale: the Chrome UX Report** The same real-user dataset, available beyond one URL: origin-level figures, history, and comparisons between sites. It answers "is my whole site slow" rather than "is this page slow".
3. **The whole site as Google groups it: Search Console** The Core Web Vitals report groups your URLs into good, needs improvement and poor, by device, from the same field data. It is the shortest path from a speed problem to a list of templates to fix.
4. **Depth on one load: WebPageTest** Filmstrips, waterfalls, many locations and devices, first and repeat views, and runs you tune one variable at a time. When the question is why, this is the instrument.
5. **A readable report you keep: GTmetrix** Built on Lighthouse, with a history of runs, test locations and monitoring on paid plans. It is the tool for watching a page over months rather than debugging one load.
6. **Your own browsing: DevTools and the Web Vitals extension** The Lighthouse and Performance panels in Chrome DevTools for a page you are working on, and the Web Vitals extension to see the metrics as you click through your own site.

## Side by side

| Tool | Data | Scope | Best question |
| --- | --- | --- | --- |
| Lighthouse | Lab, one simulated run | One page | What on this page is slow |
| PageSpeed Insights | Field and lab together | One page | Is this page failing for real users, and why |
| Chrome UX Report | Field | Origin and URL, over time | Is the site as a whole getting faster |
| Search Console | Field, grouped | Every URL of the property | Which templates fail, by device |
| WebPageTest | Lab, deep | One page, many settings | Why exactly, request by request |
| GTmetrix | Lab, built on Lighthouse | One page, over time | Has this page got slower since last month |

> Thresholds, whichever tool you use: 2.5 seconds for Largest Contentful Paint, 0.1 for Cumulative Layout Shift, 200 milliseconds for Interaction to Next Paint. Poor begins at 4 seconds, 0.25 and 500 milliseconds.

## When Lighthouse is still the right tool

- Before and after one change, on your machine, with everything else held still.
- On a page with no field data at all, which is every new page and every low-traffic page. A lab run is the only reading you can get.
- For the other three categories: accessibility, best practices and SEO audits, each scored 0 to 100, which the field data says nothing about.
- In continuous integration, where a budget can fail a build when a bundle grows.
- As a list of causes: the opportunities and diagnostics are the most actionable part of the report, whatever the score says.

Used that way, the varying score stops mattering. You are reading the list, not the number.

## What each gives up

- PageSpeed Insights: one URL at a time, and no field section when the page has too few visits.
- Chrome UX Report: no advice, only measurements, and only for sites with enough Chrome traffic to report.
- Search Console: grouped URLs, so you fix a template rather than a page, and a lag while the rolling window catches up.
- WebPageTest: no verdict, and a learning curve; free tests come with limits.
- GTmetrix: lab only, so a good score is not a passing assessment; monitoring sits on paid plans.
- DevTools and the extension: your machine, your connection, your one visit.

## The free set for a small site

1. **Monthly: Search Console** Open the Core Web Vitals report. If every group is good on mobile, speed is not your problem this month.
2. **When a group fails: PageSpeed Insights** Take one URL from the failing group. Read the field data, then the largest saving Lighthouse names underneath it.
3. **When the cause is not obvious: WebPageTest** Run the same URL on a mid-range phone over a slow connection. The filmstrip shows when the page looks finished, and the waterfall shows what arrived after that.
4. **Fix one thing and prove it** Rerun the lab test for a quick signal, then wait for the field data, because it is measured over a rolling 28-day window of real visits.

That set costs nothing and covers a product site of any size a founder is likely to have.

## The tools compared

### PageSpeed Insights

Showing one URL's real-user field data beside a fresh Lighthouse run, free and without an account. (pagespeed.web.dev)

Good at: Field and lab data on one screen; The Core Web Vitals assessment that matters for Search; Mobile and desktop tabs side by side; The opportunities list with estimated savings; Free, with nothing to install.

Choose it when You want to know whether a page is genuinely failing for visitors, and what to do about it.

Not for: Site-wide views, monitoring over time, or pages with too little traffic to have field data.

### WebPageTest

Investigating one page load in depth, from many locations and devices, with runs you tune. (webpagetest.org)

Good at: Filmstrips of what the visitor sees; Request-level waterfalls; Connection profiles and device choices; First view against repeat view; Isolating one variable per run.

Choose it when The list of opportunities did not explain the slowness and you need the evidence.

Not for: A grade, a schedule, or field data from your own visitors.

### GTmetrix

A readable speed report built on Lighthouse, with a run history, test locations and monitoring on paid plans. (gtmetrix.com)

Good at: A verdict a non-specialist can read; Keeping the history of a URL; Alerts when a page slows down; Testing from a location near your buyers; Comparing a change before and after.

Choose it when You want a page watched over months and reported to someone.

Not for: Field data, or the deep investigation of a single load.

### Chrome UX Report

The public dataset of real Chrome users' experiences, which every field reading in the other tools comes from. (developer.chrome.com/docs/crux)

Good at: Origin-level figures for a whole site; History over months; Comparing your site with another; The 75th percentile Google actually judges; Feeding dashboards without a scraper.

Choose it when You want the trend for the whole site rather than a reading for one page.

Not for: Advice, causes, or sites with too little Chrome traffic to be reported.

**Verdict.** Keep Lighthouse for what it is good at: the list of causes on one page, the accessibility and SEO audits, and a check in continuous integration. Stop reading its score as a verdict. The verdict lives in field data, which PageSpeed Insights shows for one URL and Search Console groups for the whole site, and the Chrome UX Report holds for anyone who wants the trend. When a fix is not obvious, WebPageTest is the instrument that explains a load, and GTmetrix is the one that watches a page for you over months. The free set of Search Console, PageSpeed Insights and WebPageTest covers a small product site entirely.

## Questions

### Why does my Lighthouse score change every time I run it?

A simulated load varies: network conditions, the machine, the moment, and any third-party script that behaves differently. Run it three times and compare medians, or judge changes in the field data instead, which is averaged over many real visits.

### Is a Lighthouse score of 100 a ranking advantage?

No. Google's page experience signals use field data at the Good thresholds, not the Lighthouse score. A page can score 100 in the lab and still fail the assessment on real phones, which is the reading that counts.

### What if my page has no field data?

It has too few visits for the Chrome User Experience Report to publish a reading. Use lab tools until traffic arrives, keep the origin-level data in mind, and check Search Console again once the page has been live for a while.

### Which tool measures Interaction to Next Paint?

Only field data does, because a lab tool does not click anything. PageSpeed Insights and Search Console show it once there are enough real visits; Lighthouse reports Total Blocking Time as its lab stand-in.

### Do I need a paid speed tool?

Only for monitoring and alerts. The measuring is free: Search Console for the site, PageSpeed Insights for a page, WebPageTest for the investigation. Pay when you want to be told a page slowed down without checking.

## Read next

- [Lighthouse vs PageSpeed Insights: lab and field](https://porteur.ai/compare/lighthouse-vs-pagespeed-insights): Use Lighthouse for repeatable lab checks, PageSpeed Insights for real-user field data. See why scores differ and which to trust for fixes and reporting.
- [GTmetrix vs WebPageTest](https://porteur.ai/compare/gtmetrix-vs-webpagetest): GTmetrix gives a readable report and monitoring. WebPageTest gives filmstrips, connection profiles and repeat views. Here is which to open when.
- [How to read PageSpeed Insights: field data first, then the score](https://porteur.ai/guides/how-to-read-pagespeed-insights): Start with field data, not the score. Learn what Google uses, why scores vary, and how to turn a PageSpeed Insights run into a clear order of fixes.
- [Core Web Vitals for a product site: the three numbers](https://porteur.ai/guides/core-web-vitals): The product founder’s guide to LCP, CLS and INP: what Google measures, why phones decide the pass, common causes, and how to test and fix.
- [Reading a Lighthouse score on a phone](https://porteur.ai/guides/lighthouse-score): Use the mobile Lighthouse run to judge speed and UX. See what each score means, how lab and field data differ, and what to fix first.
- [The Core Web Vitals report in Search Console, page group by page group](https://porteur.ai/guides/search-console-core-web-vitals-report): Understand where the Core Web Vitals data comes from, how page groups work, what to fix by template, and how to move groups to Good.
- [Core Web Vitals checker](https://porteur.ai/tools/core-web-vitals-checker): Paste a URL for one Lighthouse run on a simulated phone: LCP, CLS, TBT and FCP against Google's thresholds, the biggest savings, the failing audits.
- [Speed Index](https://porteur.ai/glossary/speed-index): Speed Index measures how quickly a page is visually populated, from a filmstrip of the load. Where it appears, its weight, and what it catches.

Paste your URL and the free check measures how your home page loads on a phone, beside the searches and rivals around your site, in about thirty seconds. Free check: https://porteur.ai/