Key Takeaways:

• Every second of loading time costs up to 7% of conversions
• The Core Web Vitals LCP, INP, and CLS are official Google ranking factors
• Most performance problems come from unoptimized images and too much JavaScript

53 percent of mobile users leave a website that takes longer than three seconds to load. At five seconds, it's already 90 percent. Every additional second of loading time reduces the conversion rate by an average of seven percent.

These numbers aren't theory – they come from Google studies with millions of users. The message is clear: Speed is not optional. It's the basic requirement for visitors to even become customers.

What Core Web Vitals Measure

Google evaluates user experience based on three metrics. Each measures a different aspect of performance, and all three must show good values for your website to be considered fast.

The Three Core Web Vitals Overview

LCP stands for Largest Contentful Paint and measures how quickly the main content becomes visible. For most pages, this is a large image or headline. A good LCP value is under 2.5 seconds.

INP stands for Interaction to Next Paint and has replaced FID as a metric. It measures how quickly your website responds to user actions. When someone clicks a button, the reaction should be visible in under 200 milliseconds.

CLS stands for Cumulative Layout Shift and measures whether elements shift during loading. Nothing frustrates users more than accidentally clicking the wrong button because the page shifted at the last moment.

The Most Common Performance Killers

Images are almost always the biggest problem. A single uncompressed photo can be several megabytes and double loading time. The solution is simple: compress images before upload, use modern formats like WebP, and only load the actually needed size.

Too much JavaScript slows down every website. Tracking scripts, chat widgets, social media buttons, and analytics tools add up quickly. Each individual script must be loaded, parsed, and executed. Critically review which scripts are really necessary.

Slow server response times often come from cheap hosting, non-optimized databases, or missing caching mechanisms. The server should respond in under 200 milliseconds. Anything longer delays the entire loading process.

Render-blocking resources prevent the page from displaying until all CSS and JavaScript files are loaded. Critical CSS should be inlined, unimportant JavaScript can load delayed.

Practical Optimization Measures

The most effective measures can be implemented without programming knowledge:

• Compress images: Tools like TinyPNG or Squoosh reduce file sizes by 70-80% without visible quality loss
• Enable lazy loading: Images below the visible area only load when the user scrolls
• Set up caching: Returning visitors load resources from browser cache instead of server
• Remove unnecessary plugins: Each plugin can worsen loading time
• Use CDN: Content Delivery Networks deliver content from servers near the user

Test your website regularly with PageSpeed Insights. The tool shows not only your Core Web Vitals but gives concrete recommendations on which measures will have the greatest effect.

WordPress-Specific Optimizations

WordPress websites often have performance problems due to poorly programmed themes and too many plugins. With the right settings, much can be improved.

A caching plugin like WP Super Cache or W3 Total Cache should run on every WordPress site. It saves pre-rendered pages and drastically reduces server load.

Image optimization plugins like ShortPixel or Imagify automatically compress images on upload and convert them to modern formats. This saves manual work and prevents unoptimized images from reaching the website.

Check your theme for performance. Lean themes like GeneratePress or Astra load faster than bloated multipurpose themes with dozens of unused features.

Hosting as Foundation

The best hosting determines your website's performance foundation. Cheap shared hosting shares server resources with hundreds of other websites. During traffic spikes, your site becomes slow because other websites consume the resources.

Managed WordPress hosting from providers like Raidboxes, WP Engine, or Kinsta offers optimized server configurations, automatic caching, and faster response times. The additional costs are offset by better rankings and higher conversion rates.

Pay attention to the server location. A server in Germany delivers content to German users faster than a server in the USA. Distance to the user directly affects latency.

Measuring and Documenting Success

Perform a baseline measurement before each optimization. Note the current Core Web Vitals in PageSpeed Insights and loading times in GTmetrix or WebPageTest. After each change, measure again and document the improvement.

Google Search Console shows aggregated Core Web Vitals for your entire website. Here you see how many pages have good, needs improvement, or poor values. Focus first on pages with the most traffic.

Use our SEO Analyzer, which also analyzes your website's performance metrics.

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Frequently Asked Questions

How fast should my website load?

The main content should be visible in under 2.5 seconds to achieve a good LCP value. Ideally, complete loading time should be under 3 seconds. Every second beyond that measurably costs conversions and can negatively affect rankings.

Do Core Web Vitals really affect Google ranking?

Yes, Core Web Vitals have been an official ranking factor since 2021. The influence is moderate – good content beats fast loading times. But with otherwise equivalent pages, the faster one wins. In competitive markets, this can be decisive.

Which optimization brings the most benefit?

Image optimization usually has the greatest effect. Uncompressed images are the main reason for slow loading times on most websites. Compressing all images by 70% can cut loading time in half without visible quality loss.