Webpage size mean that how much webpage content weight? The smaller the webpage size the better it is. Webpage loading speed depends upon webpage size if the webpage size is small it will load faster and user will be happy they will like it very much that website opening fastly , otherwise if webpage size is big then webpage will load slowly and user will be frusteded and may leave before it even open. So its better that your webpage size is less and loads fastly.
Useotools Webpage Size Checker is one click tool that will check your website page size within seconds. Usage of this tool is very simple you just need to input your webpage URL and press submit button then useotools server will fetch your site webpage and will calculate its size and loading speed for you so that you can tweak it if webpage size is big. Webpage size and its loading speed can be optimized in several ways like reducing assets requests from server for example if your site have 10 icons on webpage then instead of sending 10 requests to server for these icons its better to make sprites of these icons and get these icons in one request, and like that other assets like css and js files Minify them so that their site is reduced and also put them in single file so that they are served via single request.