The Grade and Summary sections of GTmetrix provide you with the following:
The Grade section indicates your website's overall rating based on both its loading speed and how well your website is built for optimal performance. Aim for an A or B rating:
If your grade is C or lower, you can improve it by fixing the top issues listed in the rest of the GTmetrix sections. Please note that:
If your website loads fast, it doesn’t automatically mean it is optimized. You can make it even faster and, therefore, more SEO-attractive with optimization
If your website is optimized, it doesn’t automatically mean it will load fast. There are other issues that can affect the website’s performance, so make sure to check them all. However, optimization is still required for fast website loading
How to Read the Summary Section
Right below the grade, you will find the Summary section with the Speed Visualization. It indicates information about all the loaded elements and how soon the visitors are able to interact with your website:
What Is TTFB?
In the speed visualization, you will find a first point labeled TTFB. It is the Time To First Byte (TTFB) - the sum of the time the server takes to respond to requests, the Redirect Duration, the Connection Duration, and the Backend Duration. This process depends on multiple factors such as network transfer speeds, latency, efficiency of the application code, and performance of the server.
Here are some reference values for TTFB, in milliseconds:
How to Reduce TTFB
Scrolling down past the Summary, you will find the top issues, which can also be consulted in the Performance tab.
Always prioritize the issues marked as High and Medium, as they will increase the website’s performance the most.
The last part of this section shows the fully loaded page time along with Total Page Size:
The recommendation is for your website to load in 2 seconds or less (2000ms). For total page size, the smaller, the better, although a size under 2MB is suggested.