To speed up your website and improve your Google PageSpeed score, you need to convert images to WebP, switch on browser caching, use a CDN, minify your CSS and JavaScript files, and choose fast hosting. Those five actions combined take most unoptimised sites from a score of 30-40 to 80-95/100 on PageSpeed Insights.
A site that takes three seconds to load loses 40% of its visitors before a single line of content has appeared. At five seconds it is 50% lost. Google also penalises slow sites through its Core Web Vitals, so performance is both a conversion issue and a direct SEO issue.
Test your website's speed for free
Which tools should you use to measure your website's speed?
To measure your website's speed, the three free tools to use are Google PageSpeed Insights (the official Google score plus Core Web Vitals), WebPageTest (a detailed resource-by-resource analysis) and Lighthouse in Chrome DevTools (prioritised recommendations). Google PageSpeed Insights is the mandatory starting point because it is the benchmark Google itself uses for ranking.
The three Core Web Vitals to watch:
A score under 50/100 on mobile is an emergency to deal with before any marketing work.
Why are images the number one cause of a slow website?
Images are the number one cause of a slow website because they account for 60 to 80% of a page's total weight and are often loaded with no compression and in the wrong format. A single uncompressed 3 MB JPEG can multiply the load time of a page that should weigh 300 KB by ten.
Image optimisations in order of priority:
Potential gain: 30 to 60% on the PageSpeed score. It is the highest-impact fix on almost every website.
How does browser caching cut load times?
Browser caching cuts load times by storing static resources (images, CSS, JavaScript) locally on the first visit, so they do not have to be downloaded again on later visits. For a returning visitor, a well-cached site loads three to five times faster than one without caching.
Cache configuration:
Is a CDN worth it for a local business brochure site?
A CDN is worth it even for a local business brochure site because it cuts network latency by serving resources from the server physically closest to each visitor. Cloudflare (free plan) also adds a layer of protection against attacks and improves LCP significantly.
Recommended CDN options:
How do you minify your website's CSS and JavaScript?
Minifying CSS and JavaScript means automatically stripping out the spaces, comments and unnecessary characters to cut file sizes by 10 to 30%. It happens automatically in modern frameworks (Next.js, Vite, Webpack) and can be handled by plugins on WordPress.
Which hosting should you choose for a fast website?
For a fast website you need hosting with servers in Europe, modern infrastructure (NVMe SSD, HTTP/3) and a built-in CDN. Cheap shared hosting (1-2€/month) is often the main reason a WordPress site scores badly on PageSpeed.
| Option | Best for | Price | Performance |
|---|---|---|---|
| Vercel | Next.js/React | Free to 20$/month | Excellent |
| Netlify | Static sites | Free to 19$/month | Excellent |
| PlanetHoster | WordPress | 4-8€/month | Good |
| Infomaniak | WordPress | 5-12€/month | Good |
| Kinsta | Premium WordPress | 35€/month | Excellent |
Every website we build at ConvertiLab is hosted on Vercel, and our clients' average PageSpeed score is 88/100 on mobile at delivery.
What results should you expect after optimising speed?
After a full speed optimisation, the typical results are a mobile PageSpeed score going from 30-50 to 85-95, an LCP going from 4-6 seconds to under 2.5 seconds, and a bounce rate falling by 15 to 25%. The SEO effect shows up 4 to 8 weeks after the fixes.
| Metric | Before optimisation | After optimisation |
|---|---|---|
| Mobile PageSpeed score | 30-50/100 | 85-95/100 |
| LCP | 4-6 seconds | Under 2.5s |
| Total page weight | 3-5 MB | Under 500 KB |
| Mobile bounce rate | 65-75% | 45-55% |
Effect on conversions:
| Load time | Effect on conversions |
|---|---|
| 1 second | Baseline (100%) |
| 3 seconds | -20% |
| 5 seconds | -50% |
| 7 seconds | -70% |
Start by optimising your images and moving to modern hosting. Those two actions alone are enough to double the PageSpeed score of most sites within a few hours.
Frequently asked questions about website speed
Does a good PageSpeed score directly improve Google rankings?
Yes, the Core Web Vitals (LCP, INP, CLS) have been confirmed Google ranking factors since 2021. A poor score will not remove a site from the results, but with equal content a fast site is favoured over a slow one. The effect is especially visible on local and long-tail searches with low competition.
My WordPress site is slow despite paid hosting, what should I do?
A WordPress site that is slow despite paid hosting is nearly always caused by too many active plugins (delete every plugin you do not use), unoptimised images (install Imagify or ShortPixel), or a heavy theme loading too many scripts. Install WP Rocket, switch off the plugins you do not need and optimise the images: in 80% of cases that is enough to get above 70/100 on PageSpeed.
Do you need a developer to optimise a website's speed?
No, most speed optimisations do not need a developer. On WordPress, plugins (WP Rocket, Imagify, Cloudflare) do 80% of the work automatically. The only optimisation that genuinely needs a developer is rebuilding the architecture (moving to a modern framework such as Next.js), and that is only necessary for genuinely complex sites.
What is the minimum acceptable PageSpeed score for a professional website?
The minimum threshold is 70/100 on mobile according to Google's guidance. Below 50 you are penalised in search and you lose visitors to the slowness. ConvertiLab websites (Next.js + Vercel) consistently reach 90 to 98 on mobile, which puts our clients among the fastest in their sector. If your score is under 70, that is your number one priority, ahead of spending anything on SEO or advertising.
