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User experience, conversion rates, search engine rankings, and overall website performance are directly affected by site speed.

Site Speed

Site speed, also known as website speed or page load time, refers to the amount of time it takes for a web page to load and display its content to users. It is a critical aspect of user experience.

User experience, conversion rates, search engine rankings, and overall website performance are directly affected by site speed. Back in 2017, Akamai found that a 100ms slowdown in site speed reduced ecommerce conversion by 7% (source link).

How to Measure Site Speed?

Probably the best resource to measure your site speed is the PageSpeed Insight tool by Google.

Here are some other tools that you can check out to test your sites frontend performance:

Also, read our blog post on frontend performance measuring and KPIs.

Measuring Core Web Vitals: PageSpeed score 100!

Measuring Global Performance

PageSpeed is based on Lighthouse. There is a dedicated tool to test your site speed globally called Lighthouse Metrics. The benefit of Lighthouse Metrics is that you get to see how your site is performing from different locations around the globe. A similar service is called Fast or Slow.

Tools to measure global site speed:

Measuring Global Site Performance: Performance scores worldwide.

Key Site Speed Metrics

There are several key metrics used to measure site speed, each focusing on different aspects of the page loading process:

  1. Time to First Byte (TTFB). The time it takes for a user's browser to receive the first byte of data from the web server. TTFB measures the server response time, reflecting the efficiency of the server infrastructure and backend processing.
  2. First Contentful Paint (FCP). The time it takes for the first piece of content, such as text or an image, to appear on the screen. FCP is an important measure of perceived load speed, as it indicates when users can start to see and engage with the page content.
  3. Largest Contentful Paint (LCP). The time it takes for the largest visible element, such as an image or text block, to load and render on the screen fully. LCP is a key indicator of visual completeness and user experience, as it marks the point when the main content of the page is available for users to engage with.
  4. Time to Interactive (TTI). The time it takes for the page to become fully interactive allowing users to perform actions such as clicking buttons or filling out forms. TTI measures the load responsiveness of a web page, which is crucial for understanding the overall user experience.

Performance Budgets

Organizations that take site speed and frontend performance seriously have dedicated teams or processes that focus on performance. The teams typically have performance budgets that define how much time or data they can allow for the different aspects of their site.

Examples of KPIs that can be used in a performance budget are total page size, number of HTTP requests, maximum image sizes, maximum JavaScript size, better FPC, or any other web vitals, etc.

When testing site speed, make sure you are not just checking the front page of your site. Product pages, blog posts, and checkout pages should all be tested for performance.

Time to interactive and page speed illustrated

Site Speed Impacts User Experience

Users expect the same performance from websites and mobile websites as they get from native mobile apps. Pinterest achieved a 15% increase in signup conversion by reducing the perceived wait time by 40% on their mobile websites. This is yet another example of how performance directly reflects the user experience.

Site Speed Directly Impacts Conversion

Conversion rates go up with every second that your website loads faster. Check the revenue faster pages may generate for your online store with our FREE Page Speed ROI Calculator.

Page Speed ROI Calculator

Site Speed Impacts SEO

Google is monitoring site speed and using it directly to rank your website in the search results. The site performance is measured when Google is indexing your website. Lately, Google has also included speed monitoring in the search console, which is a strong indication that mobile and web performance is a factor in SEO ranking.

Having a great page experience can contribute to success in Search. And page experience is strongly related to website performance. What this means is that you should focus on site speed for better performance in Search, but if you don’t pass all relevant Core Web Vitals (and the applicable factors from the Page Experience report), they will not push you down the rankings. It is just one metric, but site speed can boost your ecommerce SEO ranking.

Improving Site Speed: The Basics

We’ve covered how you can improve site speed in our frontend performance checklist, so here, let’s just mention a couple of basic optimization techniques that can help you achieve better site speed fast.

  1. Minimize HTTP requests by reducing the number of files and elements that need to be loaded.
  2. Compress images and use modern image formats to reduce file size without compromising quality.
  3. Implement browser caching to store frequently used files locally, decreasing the need for additional server requests.
  4. Minify and compress CSS, JavaScript, and HTML files to reduce file size and improve load times.
  5. Utilizing Content Delivery Networks (CDNs) to distribute content across multiple servers and reduce latency and have a better server processing time.

In conclusion, site speed is a crucial factor in determining user experience and website performance.

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