Free Tool · Lighthouse Score Calculator
How Google Scores Your Site
The Lighthouse performance score behind PageSpeed Insights is not a mystery. It is five measurements, each graded on a published curve, each carrying a published weight. The sliders start at the median page on the web, which scores exactly 50. Move them and watch exactly where every point comes from.
Google scores your site on its mobile experience first. The same numbers score differently on the desktop curves. Flip the toggle and watch the curve move.
Mobile Score
Where the points come from
Largest Contentful Paint scoring curve, mobile. Select any metric above to inspect its curve.
The curve is log-normal: the first improvements earn the most points, and the returns shrink as you approach the top. That is why going from 60 to 80 is easier than going from 80 to 95.
This is the lab model with your hands on the dials. Your real page has real numbers. Run the free audit and see them.
Run Your Free AuditCurves, weights, and control points read from the Lighthouse source, version 13.4.1, retrieved 2026-08-25. This tool models the published lab scoring math and is not affiliated with Google.
Free Tool · Website Speed Cost Calculator
What Is That Score Costing You?
The score above is a grade. This is the bill. Three independent studies have measured what load time does to conversions and bounces across hundreds of millions of visits. Put your own numbers in and see what each one says about your site, in dollars a month. Nothing here is stacked or compounded; each figure stands on its own study.
Pick what a visit is worth to you. Service businesses count leads and bookings. Shops count orders. The research behind each figure is different, so the model switches with you.
Your numbers
Sessions in Google Analytics, or your best estimate.
The share of visits that call, book or send a form.
What a new lead is worth to you on average, once you factor in how many close.
How long your page takes to load on a phone. If you are not sure, the free audit measures it.
Where a well-built site lands. Google calls anything under 2.5 s good.
What the research says
Revenue at risk each month
$1,125
Loading in 1.5 s instead of 3.0 s, the same visitors would convert at about 2.8% instead of 2.0%. On 1,000 visits a month, that is about $1,125 you are not seeing.
Modelled on Portent's 2022 conversion data, 100 million page views across 20 sites. Our interpolation between their published points.
The first tenth of a second
Deloitte's lead-generation finding: a 0.1 s improvement cut the bounce rate on lead-generation pages by 8.3%. A bounce figure does not turn into dollars without guesswork, so we do not turn it into one.
Google and Deloitte, Milliseconds Make Millions, 2020.
At 3.0 s, Google's model puts the chance a mobile visitor leaves before the page loads 32% higher than at 1 s. Google and SOASTA, 2017.
These are published averages with your numbers in them. Your real load time is a measurement, not a slider. The free audit takes it in about 30 seconds.
Measure Your Real Load TimeSources, retrieved 2026-08-30. Interpolation between each study's published points is ours and is linear. No figure is extrapolated past a study's last published point. Modelled from published industry research; your results depend on your traffic, your offer and your market.
- Google / Deloitte Digital / fifty-five, Milliseconds Make Millions (2020). 37 brand sites, ~30M mobile sessions, 30 days; a 0.1 s improvement across four speed metrics.
- Portent, Site Speed is (Still) Impacting Your Conversion Rate (2022). 100M+ page views, 20 sites (6 B2C e-commerce, 14 B2B lead generation), 30 days.
- Google / SOASTA (Think with Google), New Industry Benchmarks for Mobile Page Speed (2017). neural net at 90% prediction accuracy on bounce and conversion data.
Scores Tell You Where You Stand. Audits Tell You What to Do.
The calculator above models exactly what PageSpeed Insights measures: the lab performance of a single page. That is one dimension of one page. Modern visibility is decided across four, on every page you have. Here is how the tools compare.
Google PageSpeed Insights
Free
- Tests one page at a time.
- Performance only: the five lab metrics you just explored, plus real-user field data where Google has it.
- Gives you the score. What to do about it, and what it means for your business, is left to you.
A great instrument. Also where most analysis stops.
Xavarro Free Website Intelligence Audit
Free, about 30 seconds
- Four pillars, not one: SEO, AI search visibility, accessibility, and performance.
- Performance runs on the same PageSpeed data, scored on both the mobile and desktop models.
- Category breakdowns and an overall grade, so you can see where the points are actually lost.
The starting point. No account, no sales call, no strings.
Deep Forensic Audit
The full picture
- Crawls your site page by page, up to 50 pages, not a single URL.
- Findings tied to the specific elements causing them, prioritized by impact and effort.
- Competitor comparison and your business context folded in, and every report is reviewed by us before it reaches you.
Built for owners who want a working plan, not another score.
The free audit takes 30 seconds and answers where you stand. When you are ready to know exactly what to fix, in what order, and what it is worth, that is a conversation, not a checkout page.
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