Robert Dannelly

First Byte Time “FBT”

Blog Post created by Robert Dannelly on Jul 23, 2015


Findings on First Byte Time "FBT" while testing Web sites.


After much research using I thought is would be important to share my findings.

Points of Interest

First and foremost I hope this helps some others, I find it very important to share knowledge that will help others to improve their Web sites on the Internet.

I have been scratching my head trying to figure out why I was receiving an “F” rating on www.webpagetest.orgfor First Byte Time “FBT”.  After some research and additional testing on I have come to the following conclusions:

Reasons why First Byte Time takes so long

  1. Number of requests/responses needed to build the page
  2. Does the page have a lot of Dynamic content on the page (aka how many database calls are going back and forth for data)
  3. Size of the overall page
  4. Size of CPU and MEMORY of the HOSTING SERVER. The more powerful the SERVER the faster processing you will receive.
  5. Do you have a VM Server or a Dedicated Server


My test sample was for the home page of I got an “F” for FBT every time, that is because this page has a lot of dynamic content and unless I dissect and rebuild this page it will continue to receive an “F” although the overall page is loading in under 2 sec.  However, If I go to it gets a “B” because there is very little dynamic or programming on that page and not many images.  Finally when I run our we get an “A” because there is no images and no coding.


My overall opinion is that FBT is important, but can also be a false/positive.