In this paper, we present WePR, a web performance measurement tool for evaluating the download and the rendering time of a website at large scale. The first component of the tool, WebPerf, measures the technical metrics of a website such as DNS lookup time, TCP connection establishment time, page download time from different vantage points. The second component renders the website based on the
... [Show full abstract] metrics recorded by the WebPerf and measures the rendering time of the website in a browser window. The user experience on a website is then inferred from the measured rendering time. Along with describing WePR's architectural design and the metrics it measures, we present initial measurement results recorded March to August 2015. The results show that transmission latency, DNS lookup time, the number of HTTP elements affect the rendering time of the website and therefore the end user experience.