Why is my website slow? Causes and fixes
The most common causes of a slow website (images, hosting, plugins, JavaScript) and how to measure and improve Core Web Vitals.
A website is usually slow because of unoptimized images, too many plugins or JavaScript, low-quality hosting, third-party fonts and scripts that block rendering, and missing caching. Measure it for free with Google PageSpeed Insights: aim for LCP under 2.5 s, INP under 200 ms and CLS under 0.1 on mobile.
A slow website loses clients and rankings. The good news: the causes are almost always the same.
How to measure it
Run PageSpeed Insights on mobile and check the Core Web Vitals:
| Metric | Measures | Good |
|---|---|---|
| LCP | Time to show main content | < 2.5 s |
| INP | Response to taps and clicks | < 200 ms |
| CLS | Layout movement while loading | < 0.1 |
Common causes
- Heavy, uncompressed images.
- Too many plugins or JavaScript.
- Overloaded shared hosting.
- Third-party fonts and scripts.
- No caching or CDN.
Fixes by impact
- Compress and resize images; lazy-load below-the-fold images.
- Remove plugins and scripts that don’t drive sales.
- Enable caching and a CDN.
- Self-host fonts.
- If the platform is the limit, migrate to a modern static base (Astro, Next.js).
FAQ
Does speed affect Google rankings?
Yes. Core Web Vitals are part of Google's page experience signals. They won't make up for poor content, but between similar results the faster site has an edge and converts better.
