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Search Engine Optimisation

10 Website Speed Metrics You Should Know

Website speed metrics

Website speed is really import for user experience, SEO and conversion rates – the faster the better. Do you know what impacts website speed and how to measure them? Here are 10 website speed metrics you should know.

1. Domain Lookup Time

This is the time it takes to do the Domain Name Server (DNS) lookup. A DNS is effectively a server that tells the browser where a website is hosted (i.e. the IP address of the web server).

There’s not a great deal you can do to improve domain lookup time, other than ensure you are using a fast domain name server. This reason why we recommend clients use our dedicated name servers, as we know they are fast and reliable.

2. Server Response Time (aka Backend Time)

Server response time is the amount of time, typically expressed in milliseconds, that it takes for the network and the server to generate and start sending content after your browser has requested the page. Google recommends you should try to get server response times down to below 200 ms. 

Factors that impact server response time include network latency, the quality of the application code, the programming language and version, server specifications, and the number of sites sharing these resources.

3. Server Connection Time

Server connection time is how long it takes to establish a TCP connection to a web page.

Slow server connection times may indicate that your site is on a cheap or overloaded server.

4. Page Download Time

This is the amount of time it takes to download the HTML component of the page. 

Factors that impact page download time include the amount of content in the page, and whether the HTML is minified and compressed.

5. DOM Content Loaded Time

DOM content load time is the time a browser takes to load and parse the HTML, without waiting for stylesheets, images and other elements to load. 

Factors that impact DOM content load time include whether javascript is loaded asynchronously and stylesheets are optimised.

6. DOM Interactive Time

The time a browser takes to parse the HTML and get the page ready to request additional resources, such as CSS files and images.

7. Front End Time

Front end time is the amount of time it takes for the browser to interpret the code it receives in order to display a web page. 

Factors that impact front end time include the number of resources that are requested (e.g. images, fonts, javascript files, css files etc), the size of these resources, and how the web page is structured. Fundamentally, the fewer resources and the smaller in size, the faster the front end time but, in reality, it’s a little more complex than that.

8. Redirection Time

This is the amount of time that is spent on redirecting requests. The fewer redirects your browser has to follow, the faster the page will display. 

For example, a web page could include links to third party resources (e.g. images) that were moved. If the owners were kind enough to “tell” the browser about the new location, the browser must now make two requests to display the image, rather than only one for an image that hasn’t moved.

9. First Paint Time

This is when the first paint happens on the screen. Not all resources are required to deliver a fast first paint. It’s usually just the HTML mark up, CSS and Javascript, as images do not lock the initial render.

10. Page Load Time

Page load time is the total amount of time for a page to fully load. This is from when it is first requested to being displayed in the browser. 

There are many factors that impact page load time, in fact pretty much everything in this article!

Let us know @hileniumco if you think we’ve missed any important website speed metrics that people should know to make their websites fast.

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