How to Reduce LCP on Mobile with the Dawn Theme in Shopify

How to Reduce LCP on Mobile with the Dawn Theme in Shopify

How to Reduce LCP on Mobile with the Dawn Theme in Shopify


Good evening all! If you’ve been wrestling with reducing your Largest Contentful Paint (LCP) on mobile with the Dawn theme, you’re not alone. I’ve seen many of you ask about this in various forums, and it’s a common struggle for many Shopify users. In this detailed guide, we’ll dive deep into what LCP is, why it matters, and provide you with a step-by-step approach to reduce LCP on mobile devices specifically using the Dawn theme in Shopify.

What Is LCP and Why Is It Important?

Largest Contentful Paint (LCP) measures the time it takes for the largest content element on your website to become visible within the viewport. This could be an image, a block of text, or any other significant element. Google considers LCP an essential factor for user experience and includes it as a metric in its Core Web Vitals.

Why Should You Care About LCP?

  1. User Experience: A fast LCP improves the perceived load time and overall user experience.
  2. SEO: Google uses LCP as a ranking factor. A poor LCP can hurt your search ranking.
  3. Conversion Rates: Faster load times can lead to higher conversion rates.

Identifying Common Causes of Poor LCP

Before diving into the solution, it's crucial to understand the causes behind a slow LCP. Here are some common issues:

  1. Large Images: Unoptimized or huge images can drastically affect load times.
  2. Render-Blocking Resources: Scripts and stylesheets that block rendering can delay the LCP.
  3. Slow Server Response Times: If your server takes too long to respond, it will delay the LCP.

Steps to Reduce LCP on Mobile with the Dawn Theme

Step 1: Optimize Your Images

Optimizing images is one of the most effective ways to improve LCP. Here's how you can do it:

  1. Use Correct Formats: Convert images to modern formats like WebP for better compression.
  2. Compress Images: Use tools to compress your images without losing quality.
  3. Responsive Images: Use responsive image tags to serve different resolutions based on device type.

Step 2: Lazy Load Images

Lazy loading ensures that images outside the viewport are not loaded until the user scrolls to them. This reduces the initial load time significantly.

  1. Enable Lazy Loading: This can be done by including a loading="lazy" attribute in your <img> tags.

Step 3: Use Async and Defer for JavaScript

By default, JavaScript blocks rendering, which can delay LCP. You can add async or defer attributes to your script tags to prevent this.

  1. Async: Use async to load scripts asynchronously without blocking HTML parsing.
  2. Defer: Use defer to avoid blocking the HTML parser and execute the script once the document has been fully parsed.

How to Implement Async and Defer

Locate your JavaScript files in your theme and add the attributes. For example:

<script src="path/to/your/script.js" async></script>
<script src="path/to/your/script.js" defer></script>

Step 4: Minify CSS and JavaScript

Minifying CSS and JavaScript files reduces their size, speeding up load times.

  1. Use Minification Tools: Tools like Terser for JavaScript and CSSNano for CSS can automate this process.

Step 5: Optimize Font Loading

Fonts can also impact LCP. Use the font-display property in your CSS to control how fonts are rendered.

  1. Add Font-Display Property: Add font-display: swap; to your font-face CSS rules to render fallback fonts until the custom font loads.

Step 6: Improve Server Response Time

Server response time is crucial. Here are a few ways to optimize it:

  1. Use a Fast Hosting Provider: A high-performance server can dramatically improve response time.
  2. Enable Caching: Implement server-side caching to reduce load times for returning visitors.

Step 7: Monitor and Test Your Improvements

After implementing these changes, use tools like Google PageSpeed Insights or Lighthouse to monitor your LCP. Continue to make tweaks as necessary.


How Do I Know If My LCP Is Improving?

You can use tools like Google PageSpeed Insights to measure your LCP before and after making changes.

What If My LCP Still Isn’t Good?

Sometimes, identifying the root cause can be complex. If your LCP is still not meeting expectations, consider consulting a professional for an in-depth analysis.


Reducing LCP on mobile with the Dawn theme is achievable by following the steps outlined in this guide. Start with image optimization, use lazy loading, implement async and defer attributes for JavaScript, and minify your files. Don’t forget to monitor your site's performance to continue making improvements. By doing so, you'll enhance your user experience, boost your SEO efforts, and potentially increase your conversion rates.

Thank you for reading, and good luck optimizing your Shopify store!