So for standard HTML website, you can use tools like Web Page Test (webpagetest.org) or any other proprietary tools like GTmetrix.

The problem is that when you have an SPA built with React, Angular, Vue or any other framework, your first-page load will download all the packaged JS and CSS files.

One way I managed to better compare SPA with a standard web is to use this equation to get the Average Page Load Time:

Average Page Load Time = (LT / PS) + APL

LT - Load Time PS - Pages Per session APL - Average In-between Page Load Time (measure the time going from the home-page to the second page, like a catalog)

What do you guys think? And how are you guys managing this issue?