What are the quickest wins for improving website speed?

The three quickest high-impact improvements are: (1) Image compression and WebP conversion — often reduces page size by 50%+. (2) Enabling full-page caching — can reduce TTFB by 90%. (3) Deferring render-blocking scripts — often reduces mobile FCP and LCP by 1–2 seconds.

How long does it take to see ranking improvements after speeding up a site?

Google needs to re-crawl and re-evaluate your pages after improvements. Typical timeline is 2–6 weeks for ranking changes to reflect changes in Core Web Vitals, depending on your site's crawl frequency.

What is a CDN and do I need one?

A CDN (Content Delivery Network) stores copies of your site's assets on servers worldwide. When a user visits your site, assets are served from the nearest server rather than your origin. If your audience is geographically distributed, a CDN can reduce TTFB and asset load times by 40–80% for remote users. Cloudflare offers a generous free tier suitable for most sites.

Is it worth hiring someone to improve website speed?

Depends on the severity of the issue and your technical capability. For many WordPress sites, a non-technical site owner can achieve significant improvements by following this guide with free or low-cost plugins. For custom-built sites or severe performance issues, a developer or performance specialist can deliver more comprehensive improvements faster.

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How to Improve Website Speed: A Complete Guide

This guide covers every major technique for improving website speed — from quick wins like image compression to advanced techniques like CDN implementation, code splitting, and server-side caching. Each technique includes specific implementation guidance and expected impact.

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Quick wins to advanced optimisations

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Specific implementation steps for each technique

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Expected impact for each improvement

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Start by running the Website Speed Test to identify which areas need the most improvement, then apply the techniques most relevant to your failing metrics.

How It Works

Step-by-step guide to how to improve website speed: a complete guide:

1
Optimise images — the highest-impact quick win
Compress all images with a tool like Squoosh or TinyPNG. Convert to WebP format (30% smaller than JPEG at same quality). Add explicit width and height attributes. Use lazy loading for below-fold images. Implement srcset for responsive images.
2
Enable server-side caching
WordPress: install WP Rocket or W3 Total Cache. Shopify: caching is built-in. Custom sites: implement Varnish, Redis, or Nginx FastCGI caching. Target TTFB under 200ms after caching is enabled.
3
Reduce and defer JavaScript
Add defer or async to all non-critical scripts. Remove unused JavaScript (check coverage report in Chrome DevTools). Combine small scripts into fewer files. Consider code splitting for single-page apps.
4
Add a CDN
A CDN (Cloudflare, Fastly, CloudFront) serves your assets from servers close to each user. This reduces TTFB for geographically distributed audiences and offloads bandwidth from your origin server. Cloudflare's free tier is sufficient for most small and medium sites.

Real-world examples

Common situations where this approach makes a real difference:

WordPress site performance project

A WordPress site owner follows this guide in sequence: installs a caching plugin (TTFB drops from 1.4s to 0.12s), compresses all images with Imagify (page weight drops from 6MB to 1.2MB), defers render-blocking scripts. Mobile performance score increases from 31 to 79 over three weeks of incremental changes.

Shopify speed optimisation

A Shopify merchant applies the guide's Shopify-specific tips: removes unused apps, converts images to WebP, reduces the number of custom fonts from 6 to 2, and deactivates third-party scripts for non-essential features. Mobile LCP improves from 4.8s to 2.3s.

Developer performance reference

A front-end developer uses this guide as their primary reference document for performance best practices when building new client sites. Every new build achieves a mobile performance score of 85+ by following the techniques systematically during the build phase.

When to use this guide

Use this guide after identifying failing performance metrics, as a complete reference for website speed optimisation techniques, or when planning a systematic performance improvement project.

Pro tips

Get better results with these expert suggestions:

Fix the highest-impact issues first

Image compression and lazy loading, server-side caching, and removing unused JavaScript are consistently the three highest-impact improvements across all website types. Start with these before tackling more advanced optimisations.

Measure before and after each change

Make one change at a time and re-test after each one. This tells you exactly how much each improvement contributed to the overall score and prevents you from reverting a change that actually improved performance.

Performance is ongoing, not a one-time project

New plugins, theme updates, additional tracking scripts, and new content all add performance overhead over time. Schedule a quarterly speed audit to catch regressions before they significantly impact rankings or user experience.