WordPress SEO in 5 Minutes – What is Lazy Loading?

WordPress SEO

Page speed is no longer a “nice to have” — it is a critical ranking factor, a conversion driver, and a core component of user experience. Modern users expect websites to load in under three seconds, and research consistently shows that even a one-second delay can significantly reduce engagement, conversions, and revenue.

When a website fails to load quickly, users leave. When users leave, bounce rates increase. And when bounce rates rise, search engine rankings suffer. This cascading effect makes page speed optimisation one of the most impactful investments a business can make in its digital presence.

One of the most effective — yet often misunderstood — techniques for improving page speed is lazy loading.

In this guide, we’ll explore:

What lazy loading is and how it works
How lazy loading improves page speed and performance
The relationship between lazy loading and SEO
How lazy loading impacts Core Web Vitals
Common implementation mistakes to avoid
When lazy loading makes sense (and when it doesn’t)
Best practices for implementing lazy loading safely

By the end, you’ll have a clear understanding of whether lazy loading is right for your website and how to use it to improve both user experience and search visibility.

Why Page Speed Matters More Than Ever

Before diving into lazy loading, it’s important to understand why page speed has become such a dominant factor in SEO and digital performance.

User Expectations Have Changed

Today’s users are impatient. Mobile-first browsing, faster networks, and high-performance apps have reshaped expectations. Studies show that:

Google Explicitly Rewards Fast Websites

Google has repeatedly confirmed that page speed is a ranking factor. This became even more significant with the introduction of:

In short, faster websites tend to rank better, convert better, and retain users longer.

What Is Lazy Loading?

Lazy loading is a performance optimisation technique where only the content that is immediately visible to the user is loaded first, while the rest of the content is deferred until it’s actually needed.

Traditionally, when a user requests a webpage, the browser downloads and renders:

…regardless of whether the user ever scrolls far enough to see them.

Lazy loading changes this behaviour.

How Lazy Loading Works

With lazy loading enabled:

This ensures that the browser focuses on delivering what the user needs right now, instead of wasting resources loading content that may never be seen.

What Elements Can Be Lazy Loaded?

Lazy loading is most commonly applied to:

Images are the most frequent candidate because they often account for the largest share of page weight, especially on visually rich websites.

How Lazy Loading Improves Page Speed

Lazy loading improves page speed by reducing the that the browser must download and render.

Reduced Initial Page Weight

When fewer resources are loaded upfront:

This is especially impactful on mobile devices and slower connections.

Faster Time to First Render

Perceived speed is just as important as actual speed when it comes to user satisfaction.

By prioritising visible content:

Less Bandwidth Waste

Lazy loading prevents unnecessary downloads. If a user never scrolls to the bottom of a page:

This is particularly important for users on limited data plans.

Lazy Loading and User Experience (UX)

Page speed and user experience are inseparable. Lazy loading contributes to UX in several ways:

Faster Visual Feedback

Users are reassured when content appears quickly. Lazy loading ensures that:

Smoother Scrolling

When implemented correctly, lazy loading prevents sudden freezes or jank caused by heavy assets loading all at once.

Better Mobile Performance

On mobile devices, lazy loading:

How Lazy Loading Impacts SEO

Lazy loading can be highly beneficial for SEO, but only when implemented correctly.

Lower Bounce Rates

Slow pages frustrate users. Faster load times:

These behavioural signals indirectly support SEO performance.

Improved Core Web Vitals Scores

Lazy loading directly affects Largest Contentful Paint (LCP), one of Google’s Core Web Vitals metrics.

Lazy Loading and Core Web Vitals

Google’s Page Experience Update introduced Core Web Vitals as key performance indicators for user experience.

The three primary metrics are:

1. Largest Contentful Paint (LCP)

LCP measures how long it takes for the largest visible element (usually an image or heading) to load.

Lazy loading helps by:

Important:
The largest above-the-fold image should not be lazy loaded. Doing so can actually hurt LCP.

2. First Input Delay (FID) / Interaction to Next Paint (INP)

Lazy loading can reduce JavaScript execution during initial load, making the page:

3. Cumulative Layout Shift (CLS)

If lazy loading is poorly implemented, it can cause layout shifts when images load.

Best practice:

Can Lazy Loading Hurt SEO?

Yes — if implemented incorrectly.

Common SEO Pitfalls

Poor lazy loading setups can:

Search engines must be able to:

Best Practices for SEO-Friendly Lazy Loading

To ensure lazy loading helps rather than harms your rankings:

Use Native Lazy Loading Where Possible

Modern browsers support native lazy loading using:

Benefits:

Never Lazy Load Above-the-Fold Content

Critical content should always load immediately, including:

Maintain Proper Image Markup

This preserves accessibility and image SEO.

Always include:

Test with Google Tools

Use:

These tools reveal whether lazy loading is helping or hurting performance.

How lazy loading impacts SEO?

In 2020, Google came up with Page Experience Update that focused on the user experience on a website. This update considered several Page Experience signals, including the three Core Web Vitals metrics: Largest Contentful Paint (LCP), First Input Delay (FID) and Cumulative Layout Shift (CLS). However, Google has recently postponed its “page experience update”. Page experience will be used as a part of the ranking systems beginning in mid-June 2021, and the update page experience will not play its full role as part of those systems until the end of August. As it is a gradual rollout, businesses have enough time to rework or redesign their websites with page experience in mind.

Lazy loading mainly impacts Largest Contentful Paint (LCP), the first component of Core Web Vitals, the real-world metrics centred on user experience. Read our blog on page experience to know more. Lazy loading can also impact the way search engines crawl the site. If not executed correctly, this loading technique can accidentally hide your content from Google. Search engines can’t crawl the entire site page if your page loads slowly.

Should you implement lazy loading for your site?

It all boils down to the content and nature of your website. If you have a lot of visual content, lazy load will be helpful. You can check your site with a page speed performance tool or the Core Web Vitals report in Search Console. Go through the recommendations – defer offscreen images or anything similar needs lazy loading. You may also have a host of other recommendations to improve your technical SEO and page speed.

If you decide to implement the recommendations, our suggestion is – don’t do it yourself! Unless, of course, you are a developer. Lazy loading and all technical SEO require professional developer skills to be implemented correctly. If not done properly, you can end up breaking your site or preventing Google from properly crawling and indexing your webpages.

Have questions on lazy loading or other page speed optimisation solutions? Contact us today or email us at sales@computingaustralia.group. Our expert development and design professionals in SEO Perth can safely implement lazy loading without compromising your current online marketing efforts.

Jargon Buster

Viewport – is the area of a webpage that a user can currently view.

Crawling – is the process by which a search engine discovers webpages with the help of searchbots or crawlers.

Indexing – is the process by which search engines add and store crawled pages to their index or database for easy retrieval.

Technical SEO – is the website optimisation techniques that help your website to be crawled and indexed better.

Peter Machalski

FAQ

What is lazy loading in simple terms?

Lazy loading is a website performance technique that delays loading non-essential content until it is actually needed. Instead of loading an entire webpage at once, lazy loading ensures that only the content visible on the user’s screen loads initially. As the user scrolls, additional elements such as images or videos load dynamically. This reduces initial page load time and improves overall user experience.

Does lazy loading help SEO rankings?

Yes, lazy loading can positively impact SEO when implemented correctly. By improving page speed, lazy loading helps reduce bounce rates, enhance user engagement, and improve Core Web Vitals scores — all of which support better search rankings. However, incorrect implementation can prevent search engines from crawling or indexing content, which may harm SEO. That’s why SEO-friendly implementation is critical.

Can lazy loading negatively affect Core Web Vitals?

Lazy loading can negatively affect Core Web Vitals if critical elements are delayed. For example, lazy loading the main hero image or the largest above-the-fold element can increase Largest Contentful Paint (LCP) times. To avoid this, only offscreen or below-the-fold content should be lazy loaded, while key visual elements load immediately.

Which website elements should be lazy loaded?

Lazy loading works best for elements that are not immediately visible, including:

Below-the-fold images
Embedded videos (YouTube, Vimeo)
Iframes (maps, social media embeds)
Background images
Non-critical JavaScript

Text content, navigation, hero images, and primary calls-to-action should never be lazy loaded, as they are essential for both usability and SEO.

Should lazy loading be implemented by a developer?

In most cases, yes. While basic lazy loading may seem simple, incorrect implementation can cause layout shifts, broken functionality, accessibility issues, or SEO problems. A professional developer with technical SEO knowledge can ensure lazy loading is implemented safely, tested properly, and aligned with Google’s best practices — without risking your site’s rankings or performance.