"Is my site fast enough?" is the most frequent question we get after "how much does it cost". And luckily, the answer isn't subjective: Google has defined three precise thresholds that decide whether your site is fast enough not to hurt your search rankings. In this article we explain what to measure, how to do it for free in two minutes, and when the numbers are really telling you it's time to act.
The 3 thresholds Google actually watches (Core Web Vitals)
Since 2024, Google measures user experience for every site through three metrics called Core Web Vitals. These aren't opinions: they're numbers collected from millions of real users' browsers (via the Chrome User Experience Report, CrUX) and used as a ranking factor (Source: Google Search Central, 2025).
LCP — Largest Contentful Paint
How long the main content takes to appear on screen (usually the hero image or main heading).
- Good: under 2.5 seconds
- Needs improvement: 2.5 – 4.0 seconds
- Poor: over 4.0 seconds
INP — Interaction to Next Paint
How responsive the site is when you click on it. Replaced the older FID metric in 2024.
- Good: under 200 ms
- Needs improvement: 200 – 500 ms
- Poor: over 500 ms
CLS — Cumulative Layout Shift
How much the page content "jumps" while loading (images shifting text, banners appearing late).
- Good: under 0.1
- Needs improvement: 0.1 – 0.25
- Poor: over 0.25
To "pass" Core Web Vitals, your site must be "Good" on all three metrics, measured at the 75th percentile of real users (Source: web.dev, 2025).
How to test your site in 2 minutes (free)
The fastest way is using Google's official tool: PageSpeed Insights.
- Go to pagespeed.web.dev
- Paste your site URL
- Click "Analyze"
- Wait about 30 seconds
The tool shows two tabs: Mobile and Desktop. Look at mobile first, because it's the primary one for Google and usually the most problematic.
At the top you'll see a section "Discover what your real users are experiencing". These are your real Core Web Vitals, taken from CrUX. If the page has enough traffic you'll see colored numbers (green, yellow, red). If the site has low traffic, you may see "insufficient data" — in that case look at the lab data below, which is a simulation.
Below you'll find:
- A score from 0 to 100 (the orange/green ring image)
- Per-metric details
- A list of improvement opportunities (load smaller images, reduce JavaScript, etc.)
What the numbers mean (in practice)
Here are industry benchmarks to orient yourself before reading your results:
- On average, 41% of mobile sites on the web have a "good" CWV score (Source: Marketing LTB, 2025)
- 53% of mobile users abandon a site that takes more than 3 seconds to load (Source: WP Rocket, 2025)
- Each extra second of load time can drop conversions by up to 20%
- A site that loads in 1 second has a 7% bounce rate; one that loads in 5 seconds, 38%
Translation: if your mobile PageSpeed score is below 50, you're losing visitors and conversions in measurable ways. Above 75 you're fine. Between 50 and 75 there's room to work, but it's not a disaster.
The 3 most common problems (and how to spot them)
1. Oversized images
Symptom: in the report you see suggestions like "Efficiently encode images" or "Serve images in next-gen formats". Solution: convert to WebP/AVIF, resize to actual display dimensions, lazy-load images below the fold.
2. Excess JavaScript and CSS
Symptom: messages like "Reduce unused JavaScript" or "Reduce unused CSS". Typical of generic templates or WordPress sites with many plugins. Solution: remove unused plugins/scripts, code splitting, minification.
3. Slow hosting (high TTFB)
Symptom: the TTFB (Time to First Byte) metric exceeds 600 ms. The problem isn't the site, it's the server. Solution: faster hosting, CDN, server-side caching.
Complementary tools (useful but more technical)
If PageSpeed Insights isn't enough, here are the tools we use internally:
- Lighthouse in Chrome DevTools (right-click > Inspect > Lighthouse). Same tech as PageSpeed Insights but with more test options (Source: Chrome for Developers, 2025)
- WebPageTest.org for more detailed tests with full waterfall
- CrUX Dashboard to track your Core Web Vitals over time
- Google Search Console > Core Web Vitals report, where Google directly flags pages in trouble
When a "slow" site is salvageable and when not
Our clients almost always ask: "Do I need to redo everything, or can it be fixed?". It depends:
- Fixable (1-3 weeks): heavy images, weak hosting, too many plugins, redundant CSS/JS. Targeted optimizations on an existing site.
- Serious intervention (1-2 months): bad theme/template choice, site structure to rethink, too many third-party scripts.
- Worth rebuilding (3-4 months): obsolete code, abandoned CMS, technologies Google struggles to index.
The honest advice: do the PageSpeed Insights test first, then compare results with an agency or developer. If the issues fall in the first two categories, a targeted fix costs much less than rebuilding the site.
Conclusion
Core Web Vitals aren't a technical detail for nerds: they're how Google decides whether to show you more or less often in search results, and also why your visitors stay or leave in the first 3 seconds.
The test is free and takes 2 minutes. If the numbers say there's work to do, tell us about your business: we'll honestly tell you whether the site is fixable or worth rebuilding. Half-hour call, free. .