Conceptually, increasing your Google Pagespeed score on Shopify, BigCommerce and Magento is the same, but they differ in execution. This is because each platform handles front and backend a little differently. The first thing you need to do is understand how Google calculates the score and then we can start to breakdown how speed optimization is accomplished.

Since 2018 Google uses Lighthouse as it’s engine when scoring website PageSpeed scores. The score is a weighted average (see percentages below), based on five primary audits which include First Contentful Paint, Speed Index, Largest Contentful Paint, Total Blocking Time, Cumulative Layout Shift.

Let’s understand these a bit better:

  • FCP – First Contentful Paint – 10%
    • Your score is compared against other websites in the HTTP archive
    • Time it takes the browser to display the first DOM element
      • Tip: Font load time is often a factor that will effect this audit score
  • Speed Index – 10%

Scores can fluctuate due to changes in underlying conditions, including internet traffic, devices used for testing, local software (eg antivirus) and changes site assets (eg homepage creative, videos etc).