Running your site through PageSpeed Insights and getting back a low score is a common (and slightly demoralising) moment. A score in the red (0-49) or amber (50-89) range isn't just a number - it means real visitors are waiting longer, leaving sooner, and converting less. The good news is that most low scores come down to a small set of recurring causes, and fixing the biggest ones first moves the number a lot faster than chasing every minor suggestion on the report.
Why Speed Matters More Than the Score Suggests
Speed is the first impression your website makes, and it costs you in two ways:
- Visitors leave. Google's own research found that 53% of mobile visits are abandoned if a page takes longer than three seconds to load (Think with Google). Those are potential customers walking away before they see what you offer, and slower pages convert fewer of the visitors who do stay.
- Rankings suffer. Since 2021 Google has used Core Web Vitals as a ranking signal. There are three:
- Largest Contentful Paint (LCP) - how quickly the main content appears. Aim for 2.5 seconds or less.
- Interaction to Next Paint (INP) - how fast the page responds when someone taps or clicks. Aim for 200 milliseconds or less. INP replaced the older First Input Delay (FID) metric in March 2024.
- Cumulative Layout Shift (CLS) - whether the layout jumps around while loading. Aim for 0.1 or less.
Our Core Web Vitals guide explains each one in depth. The rest of this guide is about the fix list: what actually moves the numbers, in order of impact.
What the PageSpeed Score Actually Measures
PageSpeed Insights (pagespeed.web.dev) is Google's free tool that scores a page from 0-100 based on Lighthouse performance data, combined (where available) with real-world Core Web Vitals data from Chrome users who've visited the page. Alongside the score, it returns a list of opportunities (specific changes that would help most) and diagnostics (additional issues worth addressing).
The Fixes That Move the Score Most
1. Compress and Resize Images
Oversized images are the single most common cause of a poor score - a 4MB photo displayed at 400px wide is downloaded at full size and shrunk by the browser, wasting bandwidth and load time.
- Compress images before uploading - tools like Squoosh (squoosh.app) or TinyPNG reduce file size without visible quality loss
- Convert to WebP or AVIF - typically 25-35% smaller than JPEG or PNG at the same visual quality
- Add explicit
widthandheightattributes so the browser reserves the right space (this prevents layout shift while the page loads) - Use
loading="lazy"on images below the fold so they only download when a visitor scrolls to them
2. Eliminate Render-Blocking Resources
CSS and JavaScript that must fully download before the browser can display anything leave visitors staring at a blank or partially rendered screen.
- Add
deferorasyncto non-critical JavaScript so it loads in the background - Avoid loading large third-party scripts (chat widgets, analytics, ad tags) in the page
<head>, where they block rendering - Identify critical CSS - the styles needed for above-the-fold content - and inline it directly in the
<head>
3. Reduce Server Response Time (TTFB)
TTFB (Time to First Byte) is how long your server takes to start sending data after a visitor's browser makes a request - a slow server adds latency to every step that follows, before optimisation even starts.
- Choose a fast hosting provider - shared hosting on a busy server is the most common cause of slow TTFB
- Enable server-side caching so repeated requests are served from memory rather than reprocessed each time
- Use a CDN (Content Delivery Network) to serve files from servers physically closer to your visitors
4. Minimise Layout Shift
Cumulative Layout Shift (CLS) - one of the three Core Web Vitals - measures how much content unexpectedly jumps around as a page loads, like an image popping in and pushing text down, or a cookie banner shoving the button you were about to tap.
- Add
widthandheightto all images and video embeds so the browser reserves the correct space before they load - Avoid inserting content (banners, adverts, notifications) above existing content after the page has already rendered
- Use CSS
min-heighton containers that load dynamic content
5. Trim Third-Party Scripts and Unused Code
Chat widgets, analytics tools, ad networks, and embedded content (YouTube videos, social widgets) each add their own load time on top of your site's - and many sites also ship large JavaScript frameworks or CSS libraries while only using a fraction of them, with the rest still downloading and delaying rendering. Audit what's actually necessary and remove or defer anything that isn't earning its place. Trimming unused framework code typically needs developer help (code splitting, removing unused libraries), but auditing and cutting unnecessary third-party scripts is something most site owners can do directly.
What Score Should You Aim For?
- 90-100 (green): Good - the focus now is keeping it here as you make other changes.
- 50-89 (amber): Needs improvement - real users are noticing the delay.
- 0-49 (red): Poor - this is affecting your conversions and your rankings.
Mobile scores are almost always lower than desktop; that's normal and expected. A mobile score of 65-75 with green Core Web Vitals field data is a solid result for most small business sites.
What Not to Obsess Over
A perfect 100 score isn't the goal, and chasing it can cost more time than it's worth. Google itself has said a "good" Core Web Vitals result matters more for rankings than the specific PageSpeed number - and a site with a 73 that loads fast on real devices beats one over-optimised to score 92 in a lab test but delivers a poor experience in the real world. Focus on the field data and the specific items under "Opportunities" in your report, fix the highest-impact ones first, and re-test. Small, consistent improvements compound over time.
Where to Start
Rather than guessing which fix applies to your site, run a scan and work from the specific issues it flags, in order of impact. AuditCrow's scan checks common speed bottlenecks (large images, render-blocking resources, missing compression) alongside your broader technical fundamentals - covered in our technical SEO checklist - flags each issue in plain language with a difficulty rating, and prioritises what to fix first.
