The factors that genuinely affect page speed, Google's Core Web Vitals thresholds, how to measure them, and a prioritised list of fixes for small sites.
Slow sites lose visitors, and page experience is one of the signals Google uses. The good news is that most speed problems on small sites come from a few causes, and the biggest gains are often free. This guide explains what to measure, what the numbers mean and what to fix first.
Measure first
Use free tools rather than guessing:
- PageSpeed Insights shows lab results and, where enough visitors use the site, real-world data from Chrome users.
- Google Search Console reports Core Web Vitals across your whole site.
- Your browser's developer tools show every file a page loads, its size and how long it takes.
Test on mobile settings, because most visitors use phones and mobile connections are slower.
Core Web Vitals explained
- Largest Contentful Paint (LCP): how long the main content takes to appear. Good: 2.5 seconds or less.
- Interaction to Next Paint (INP): how quickly the page responds when someone taps or clicks. Good: 200 milliseconds or less. INP replaced First Input Delay as a Core Web Vital in March 2024.
- Cumulative Layout Shift (CLS): how much the layout jumps around while loading. Good: 0.1 or less.
Google assesses these at the 75th percentile of page visits, so most visitors, not just the fastest, should get a good experience.
What really slows sites down?
Large images
The most common problem. A photo straight from a phone can be several megabytes. Resize images to the size they are displayed, compress them, and use modern formats such as WebP or AVIF. Add loading="lazy" to images below the fold, but not to the main image at the top.
Too much JavaScript
Plugins, chat widgets, trackers and page builders add scripts that the browser must download and run, which hurts INP. Remove what you do not need, and load the rest after the main content.
Slow server response
If the server takes a long time to send the first byte, everything else waits. Causes include cheap overloaded hosting, no caching and a slow database.
No caching
Page caching serves ready-made pages instead of building each one from scratch. Browser caching lets returning visitors reuse files.
Distance
Data takes time to travel. A content delivery network (CDN) stores copies of your files in many locations, closer to visitors.
Fonts and layout shifts
Web fonts can delay text, and images or adverts without set dimensions make the page jump. Set width and height on images and reserve space for ads and embeds.
A prioritised fix list
- Compress and resize images. Often the biggest single win.
- Turn on caching, through your host or a reputable caching plugin.
- Use a CDN. Many have free tiers.
- Remove unused plugins and third-party scripts.
- Set image dimensions and reserve space for embeds to fix CLS.
- Limit web fonts to one or two families and weights, with
font-display: swap. - Upgrade hosting if server response stays slow after the above.
- Retest after each change, so you know what helped.
Don't chase a perfect score
A score of 100 is not the goal: real visitors' experience is. A page that passes Core Web Vitals and feels fast on a mid-range phone is in good shape. Speed is one factor among many; useful content matters more for search.
Frequently asked questions
Does hosting matter more than anything else?
It matters for server response time, but on most small sites, images and scripts have more effect.
Will a page builder slow my site?
Some add a lot of code. If speed matters, test a page with and without it.
How often should I check speed?
After any major change (a new theme, plugin or advert setup) and every few months otherwise. Search Console will also email you if Core Web Vitals problems appear.
Sources and further reading
- web.dev: Web Vitals
- web.dev: Interaction to Next Paint (INP)
- Google: PageSpeed Insights
- Google Search Central: Page experience
Facts checked on 20 October 2026. Spotted an error? Tell us and we will correct it.