While Google Analytics is incredibly helpful for monitoring your website popularity and visitor statistics, one thing it can't do is to tell you exactly how much bandwidth your site is using. ... Fortunately, you can use Google Analytics data to estimate your bandwidth usage.
Source: https://www.techwalla.com/articles/bandwidth-usage-in-google-analytics
Google uses sample data which is a best approximation while Webready shows the real-time, accurate data since it’s on our server.
Things to note:
Google measures page views, while Webready counts are based on the images on the pages.
Webready does not take into account any text that is on the page, only images so the bandwidth figures are less than the actual total bandwidth.
Since Google Analytics does not measure bandwidth, you would have to go on each page and go to Network settings to check the MB transferred. If you check your browser’s network data while viewing a page on the website, you will be able to see the total bandwidth for that page, filtering by images will show the bandwidth based on images only, as measured by Webready.
The values seen here depend on the device being used to view the website. Larger displays will see larger bandwidth usage.Google analytics request rate is based on the website views for a specific date. If the Home page, for instance, has 57 images, if there are 100 users on your website for 1 day who view the home page only, that will automatically be 570 image views.
When viewing the pages with images, such as an image gallery, although you may see 1 version of that image, there are actually multiple versions of that image downloaded to cater for different display sizes/orientations. For instance, changing your desktop view to landscape view will show a different, scaled version of the image.
The device size that the website is viewed on will affect the bandwidth usage as well, because different size images will be loaded depending on the screen size. The website images viewed on a mobile device will be smaller than those viewed on a desktop.
The bandwidth used for a site will also depend on the browser that a guest views it on. Some browsers will store images in the cache so even if you refresh that page, it will not need to download the images again. However, some browsers will always re-download the images, resulting in higher bandwidth use - Webready has no control of this. Also, for those browsers that cache the images, if the guest continuously refreshes the page, then some browsers will then re-download the images.
Webready calculates the number of persons who visit the website on a particular day from capturing the unique IP addresses. This can be done for 1 day, 2 days, a month etc. Google Analytics, on the other hand, captures the amount of users on a per-page basis.
Webready captures 3 things:
The number of images requested for a date range.
The total bandwidth consumed by IP address or image URL.
The total visitors for the date range.
Since Webready does not display page views, to calculate the image views and compare it using the statistics provided by Google Analytics or other analytics platforms:
Using 2-5 of the most viewed pages from your analytics platform, get the number of images (Webready support can assist with this) and calculate the image views as shown below.
Total images in the top-visited pages divided by the amount of top-visited pages => average images per page.
Average images per page multiplied by total page views (from Google Analytics) => total image views.
Compare the total image views calculated from the above steps, against image requests from Webready stats.