How to Reduce LCP and FCP for Mobile Site Speed Improvement: Troubleshooting Pagespeed and GTmetrix Issues

How to Reduce LCP and FCP for Mobile Site Speed Improvement: Troubleshooting Pagespeed and GTmetrix Issues

How to Reduce LCP and FCP for Mobile Site Speed Improvement: Troubleshooting Pagespeed and GTmetrix Issues


In today's ecommerce landscape, site speed plays a crucial role in user experience, conversion rates, and SEO rankings. When tools like Pagespeed Insights and GTmetrix fail to provide site speed recommendations, it can be a challenging task to identify what’s causing the performance issues on your Shopify store. In this guide, we’ll dive deep into common reasons why these tools might not show insights or recommendations and provide actionable solutions to reduce Largest Contentful Paint (LCP) and First Contentful Paint (FCP) for mobile site speed improvement.

Understanding the Key Metrics: LCP and FCP

Before we get into troubleshooting Pagespeed and GTmetrix, it's essential to understand what LCP and FCP are and why they matter:

Largest Contentful Paint (LCP)

LCP measures the time it takes for the largest content element in the viewport to become visible. This element is usually an image, video, or a large block of text. A good LCP score is under 2.5 seconds.

First Contentful Paint (FCP)

FCP indicates the time it takes for the first piece of content to be rendered on the screen. This metric helps you understand how quickly the initial visuals (like logos or text) are loaded. A good FCP score should be under 1.8 seconds.

Why Pagespeed and GTmetrix Might Not Show Insights

Server/Hosting Issues

One of the main reasons these tools might not provide insights is due to server or hosting problems. If your server is slow or overloaded, it can lead to incomplete or failed tests.

Blocked Content

Another common issue is blocked content. Elements that are not accessible due to permissions, robot.txt settings, or other restrictions can prevent Pagespeed and GTmetrix from fully analyzing your site.

Heavy JavaScript Execution

Too much JavaScript or poorly optimized scripts can also cause these tools to fail in loading your website fully. This can lead to incomplete data and lack of recommendations.

Cookies and Pop-Ups

Cookies, pop-ups, or any other intrusive elements that appear immediately can disrupt the testing process, causing inaccurate results.

Steps to Troubleshoot and Improve LCP and FCP

Step 1: Use Lighthouse in Chrome DevTools

Google's Lighthouse tool, available within Chrome DevTools, can give you insights into your site's performance. Here’s how to use it:

  1. Open your site in Chrome.
  2. Right-click and select "Inspect" to open DevTools.
  3. Navigate to the "Lighthouse" tab.
  4. Run an analysis and review the reported metrics.

Step 2: Optimize Images

Large images can significantly affect LCP. Here’s what you can do:

  1. Compress images without compromising quality using tools like TinyPNG or ImageOptim.
  2. Implement lazy loading to delay the loading of off-screen images.
  3. Use responsive images to serve different sizes based on the user’s device.

Step 3: Minify and Compress Resources

Reducing the size of HTML, CSS and JavaScript files can drastically improve load times:

  1. Use tools like UglifyJS for JavaScript and cssnano for CSS to minify files.
  2. Enable Gzip compression on your server to reduce resource sizes.

Step 4: Reduce JavaScript Execution Time

Reducing JavaScript execution time can improve both LCP and FCP:

  1. Limit the use of heavy libraries and frameworks.
  2. Defer non-critical JavaScript to load after the main content.
  3. Consider code-splitting to load only what's needed on initial load.

Step 5: Optimize Web Fonts

Custom fonts can also delay the rendering of your site’s content:

  1. Use modern font formats like WOFF2.
  2. Implement font-display: swap; in your CSS to improve font loading.

Step 6: Reduce Server Response Times

Improving server response times can have a direct positive impact on LCP and FCP:

  1. Utilize a Content Delivery Network (CDN) to serve content faster to users globally.
  2. Optimize your server configuration and database queries.
  3. Consider upgrading your hosting plan if you frequently encounter slow response times.


Improving your Shopify store's mobile site speed by focusing on LCP and FCP is crucial for enhancing user experience and boosting SEO rankings. By troubleshooting common issues that prevent Pagespeed Insights and GTmetrix from showing recommendations and following the actionable steps outlined above, you can significantly improve your site’s performance.


Why is reducing LCP and FCP important?

Reducing LCP and FCP is vital for improving user experience and achieving better SEO rankings. Faster load times lead to higher user satisfaction and lower bounce rates.

What should I do if Pagespeed and GTmetrix still don’t show recommendations?

If these tools still fail to provide recommendations, consider consulting a Shopify expert or a web performance specialist. They can conduct an in-depth analysis and provide customized solutions.

By following this comprehensive guide, you’re well on your way to optimizing your mobile site speed and solving any underlying issues with Pagespeed and GTmetrix. Happy optimizing!