What Is Total Blocking Time (TBT)?


Total Blocking Time (TBT) is the time it takes for a page to become fully interactive. It is measured from when the page starts loading until the last element on the page becomes interactive. You my have seen this metric when testing your website on PageSpeed.

Total Blocking Time can be affected by several factors, including server response time, network latency, and JavaScript execution time. If these factors are slow, it can increase the Total Blocking Time.

Total Blocking Time is an important metric when optimizing your website or web application. A slow Total Blocking Time can lead to a poor user experience, as users may have to wait a long time for a page to become fully interactive.

How is Total Blocking Time calculated?

Total Blocking Time is the sum of all time spent waiting for a network resource to load. This includes time spent waiting for the DNS to resolve, the initial connection, and any redirects. It also includes time spent during the SSL handshake and downloading the response body.

Why is Total Blocking Time important?

Total Blocking Time is crucial because it is a metric that can be used to measure a website’s performance. It can be used to identify areas of a website that need improvement and to track the progress of those improvements.

Total Blocking Time is calculated by measuring the time from when a user initiates an action on a page (such as clicking a link) to when the response from the server is received. The time spent between these two events is considered Total Blocking Time.

There are a few things that can cause high Total Blocking Time:

 – Slow server response times

 – JavaScript that takes too long to execute

 – CSS that takes too long to load

Improving Total Blocking Time can be accomplished by optimizing any of these areas that are causing delays. For example, if JavaScript takes too long to execute, you could try minifying it or reorganizing it, so it loads faster. Or, if your server response times are slow, you could try caching or other optimization techniques.

In general, reducing Total Blocking Time will result in a better user experience for your website visitors. A fast website will keep users engaged and reduce the likelihood of them leaving before they can convert into customers.

How can I figure out my Total Blocking Time?

Total Blocking Time is the amount of time a user spends waiting for a page to load. It is calculated by adding the time spent on each element that makes up the page.

The Total Blocking Time can be found in the Developer Tools section of your browser. To access it, open the Developer Tools (press F12 or Ctrl+Shift+I in most browsers) and select the “Network” tab. The Total Blocking Time will be listed under the “Time” column. You can also run a Google PageSpeed insights test.


Total Blocking Time is a metric that measures the amount of time a page is blocked from rendering. This can be caused by various factors, such as JavaScript and CSS files that must be correctly optimized. To calculate Total Blocking Time, you need to measure the time from when the HTML document starts loading until it is fully rendered. There are many tools available that can help you do this, so be sure to choose one that best suits your needs.

If you have any questions about total blocking time or want to optimize your WordPress website, feel free to contact us. We can help!

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