Time To Last Byte (TTLB)
Collected from: Network traffic analysis
The Time to Last Byte measures the delay between the request sent by the browser and the receiving of the last byte of the related response (the last piece of the HTML document). Thus, TTLB directly follows the Time to First Byte (TTFB). The Time to Last Byte counts an additional delay compared to the Time to First Byte: the time to download the data.
The difference between the start time (TTFB) and the end time (TTLB) is usually minor, except when the HTML page has an high page weight (relatively to the downstream bandwidth used for the speed test).