Watch for changes
sunlightfoundation.com loads faster with WebSpeed
Measured PageSpeed before and after WebSpeed optimization — no plugins, no migration.
Speed Index from a single check. Repeat checks of the same page typically differ by around 30%, so read the two times as a direction, not a precise multiplier.
From the measured LCP gain: −15.8 s.
Core Web Vitals are a Google ranking signal, but work as a “tiebreaker” — they matter most when two pages are roughly equal in relevance and content. The biggest SEO benefit comes from moving out of the Poor zone (score < 50).
From the measured LCP gain: −15.8 s.
Google / Deloitte (2019): 0.1 s improvement → +8% conversions in retail. Portent: each extra second of load time reduces conversion rate ~4%.
From the measured LCP gain: −15.8 s.
Based on Google data: pages loading in 3 s vs 1 s show ~32% higher bounce rate. Estimate scales proportionally to LCP improvement and is site-specific.
From the measured page weight: ≈ 2.8 → 0.77 g per visit.
Transferred bytes × ≈0.5 g of CO₂ per MB, a common average for networks and devices. The real figure depends on the hosting and the visitor’s connection.
Forecasts, not measurements: measured gains × published studies — tap any underlined label for the source.
Lighthouse recording of the original page under real mobile throttling. The right panel replays the same frames at the measured Speed Index ratio (1.7× faster). Played back 1.4× faster than real time — both panels equally.
Fastest quarter 80+ · you 68
Fastest quarter 96+ · you 75
Fastest quarter ≤ 3.4 s · you 4.5 s
Fastest quarter ≤ 0.9 s · you 1.1 s
Fastest quarter ≤ 3.7 s · you 30.2 s
Fastest quarter ≤ 0.9 s · you 4.9 s
Fastest quarter ≤ 1.1 MB · you 5.6 MB
Fastest quarter ≤ 1.3 MB · you 15.4 MB
Based on 2818 WordPress sites WebSpeed has measured, as they are, without our optimization. Updated 8 Nov 2026.
Speed
what the visitor sees| Metric | Now | Fast | Δ |
|---|---|---|---|
| PageSpeed scoreblends the five below | 68 | 95 | +27 |
| First Contentful Paint. The moment the browser renders the first piece of real content — the first sign to the visitor that the page is loading.≤ 1.8s | 2.3 s | 1.0 s | −58% |
| Largest Contentful Paint. The time it takes for the largest image or text block in the viewport to render — one of Google's three Core Web Vitals.≤ 2.5s | 30.2 s | 2.9 s | −90% |
| How quickly the visible part of the page fills in during load, averaged over time — a lab metric that rewards showing content sooner.≤ 3.4s | 4.5 s | 2.6 s | −42% |
| Total Blocking Time. The total time the main thread was blocked by long tasks during load — the lab metric that stands in for real-world responsiveness.≤ 200ms | 0 ms | 0 ms | No change beyond run-to-run noise. |
| Cumulative Layout Shift. A score for how much visible content unexpectedly jumps around while the page loads — one of Google's three Core Web Vitals.≤ 0.1 | 0.084 | 0 | −0.08 |
| LCP breakdownobserved load, no throttling | |||
| What the largest visible element was — an image or a block of text. The two are sped up by different means. | Image | Image | same |
| Time until the first byte of the HTML arrived.TTFB | 2 ms | 13 ms | No change beyond run-to-run noise. |
| Time between the first byte and the moment the browser started downloading the LCP image. Long when the image is found late — lazy-loaded, set from CSS or JS.until the image is requested | 916 ms | 220 ms | −76% |
| Time spent downloading the LCP image itself — its weight and the connection.downloading the image | 352 ms | 32 ms | −91% |
| Time between the resource being ready and the element being painted — blocked by CSS, fonts or scripts.until it is painted | 1.2 s | 1.0 s | −12% |
Page weight
loaded during the test| Metric | Now | Fast | Δ |
|---|---|---|---|
| Files the browser downloaded during the test. | 46 | 25 | −21 |
| The page itself, before anything it references. | 18 KB | 116 KB | No change beyond run-to-run noise. |
| Scripts downloaded during the test. Fewer can mean deferred past the test window, not removed from the site. | 8118 KB | 864 KB | −46% |
| Stylesheets downloaded during the test. | 574 KB | 268 KB | No change beyond run-to-run noise. |
| Web font files downloaded during the test. | 17361 KB | 26 KB | −98% |
| Images downloaded during the test. Images below the fold may load later, after the test. | 155.1 MB | 121.4 MB | −72% |
| Third-partyother companies’ servers | |||
| Distinct third-party domains the page downloaded from — analytics, chat, embeds, fonts, CDNs. | 4 | 2 | −2 |
| Bytes downloaded from those third-party domains. | 410 KB | 41 KB | −90% |
What holds the main thread
Lighthouse attribution, lab runAlready on this site
Original page, before Fast- No speed tools recognisedNo caching plugin, CDN or speed host left a trace in the page’s code or headers
- Main image is marked high priorityMissing
- Images are in modern formats and sized to the screenMissingLighthouse estimate: −24.4 s LCP
- No CSS or JS holds back the first paintMissing
- Static files are cached in the browserMissingLighthouse estimate: −26.5 s LCP
- CSS and JS are minifiedMissingLighthouse estimate: −150 ms LCP · −32 KB
- Text stays visible while web fonts loadMissing
- Main image is in the HTML, not added by a scriptOK
- Main image is not lazy-loadedOK
- The page is compressed (gzip or brotli)OK
- Admin area
/wp-admin/and/wp-login.phppass through Fast unchanged and are never cached
Tools are recognised from the page’s code and response headers. A tool that leaves no trace there is not listed.
“OK” means Lighthouse found nothing to fix on the original page — not that someone switched it on.
Savings are Lighthouse’s own estimates for the original page, not measured by us.
Speed
what the visitor sees| Metric | Now | Fast | Δ |
|---|---|---|---|
| PageSpeed scoreblends the five below | 75 | 94 | +19 |
| First Contentful Paint. The moment the browser renders the first piece of real content — the first sign to the visitor that the page is loading.≤ 1.8s | 0.6 s | 0.3 s | −52% |
| Largest Contentful Paint. The time it takes for the largest image or text block in the viewport to render — one of Google's three Core Web Vitals.≤ 2.5s | 4.9 s | 0.7 s | −86% |
| How quickly the visible part of the page fills in during load, averaged over time — a lab metric that rewards showing content sooner.≤ 3.4s | 1.1 s | 2.4 s | +126% |
| Total Blocking Time. The total time the main thread was blocked by long tasks during load — the lab metric that stands in for real-world responsiveness.≤ 200ms | 0 ms | 0 ms | No change beyond run-to-run noise. |
| Cumulative Layout Shift. A score for how much visible content unexpectedly jumps around while the page loads — one of Google's three Core Web Vitals.≤ 0.1 | 0.089 | 0 | −0.09 |
| LCP breakdownobserved load, no throttling | |||
| What the largest visible element was — an image or a block of text. The two are sped up by different means. | Image | Image | same |
| Time until the first byte of the HTML arrived.TTFB | 4 ms | 2 ms | No change beyond run-to-run noise. |
| Time between the first byte and the moment the browser started downloading the LCP image. Long when the image is found late — lazy-loaded, set from CSS or JS.until the image is requested | 965 ms | 142 ms | −85% |
| Time spent downloading the LCP image itself — its weight and the connection.downloading the image | 221 ms | 16 ms | −93% |
| Time between the resource being ready and the element being painted — blocked by CSS, fonts or scripts.until it is painted | 59 ms | 182 ms | +122 ms |
Page weight
loaded during the test| Metric | Now | Fast | Δ |
|---|---|---|---|
| Files the browser downloaded during the test. | 47 | 28 | −19 |
| The page itself, before anything it references. | 18 KB | 116 KB | No change beyond run-to-run noise. |
| Scripts downloaded during the test. Fewer can mean deferred past the test window, not removed from the site. | 8118 KB | 864 KB | −46% |
| Stylesheets downloaded during the test. | 574 KB | 268 KB | No change beyond run-to-run noise. |
| Web font files downloaded during the test. | 17361 KB | 26 KB | −98% |
| Images downloaded during the test. Images below the fold may load later, after the test. | 1614.9 MB | 1511.3 MB | −24% |
| Third-partyother companies’ servers | |||
| Distinct third-party domains the page downloaded from — analytics, chat, embeds, fonts, CDNs. | 4 | 3 | No change beyond run-to-run noise. |
| Bytes downloaded from those third-party domains. | 410 KB | 52 KB | −87% |
What holds the main thread
Lighthouse attribution, lab runAlready on this site
Original page, before Fast- No speed tools recognisedNo caching plugin, CDN or speed host left a trace in the page’s code or headers
- Main image is marked high priorityMissing
- Images are in modern formats and sized to the screenMissingLighthouse estimate: −4.1 s LCP
- No CSS or JS holds back the first paintMissing
- Static files are cached in the browserMissingLighthouse estimate: −4.4 s LCP
- CSS and JS are minifiedMissingLighthouse estimate: −50 ms LCP · −32 KB
- Text stays visible while web fonts loadMissing
- Main image is in the HTML, not added by a scriptOK
- Main image is not lazy-loadedOK
- The page is compressed (gzip or brotli)OK
- Admin area
/wp-admin/and/wp-login.phppass through Fast unchanged and are never cached
Tools are recognised from the page’s code and response headers. A tool that leaves no trace there is not listed.
“OK” means Lighthouse found nothing to fix on the original page — not that someone switched it on.
Savings are Lighthouse’s own estimates for the original page, not measured by us.
PageSpeed scores are measured by Google PageSpeed Insights and are not guaranteed: they vary run to run and depend on network, device and third-party code. How to read this report
PageSpeed 68 → 95 on mobile and 75 → 94 on desktop, the screen fills in 2.6 s instead of 4.5 s on mobile and the page weighs 1.5 MB instead of 5.6 MB.
Still on the site itself: the main image is not marked high priority, images are not in modern formats or sized to the screen, CSS or JS holds back the first paint, and 3 more — listed under “Already on this site” in Speed metrics.
Get this speed for your visitors — WebSpeed Fast, 14 days free. Edit the page code yourself — the report lists the changes.
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Subscriptions start with a 14-day free trial (Fast and Growth). After it, Fast is billed yearly, and Growth and Custom run for a minimum of 6 months — you commit only after the trial. Fast is priced by monthly visits; indicative launch pricing.
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