How to test site speed

Everybody wants a faster loading website. Research shows that a faster site leads to a higher conversion rate. Google also stated that loading time is a ranking factor. In this post we want to answer the question of how to test WordPress site speed and how to identify opportunities to improve your site speed.

How to test WordPress site speed

There are numerous tools available on the internet to test your site speed. They all work on the same basic principle of retrieving a webpage like a real user would. A lot of tools let you choose the location from which to test. At Savvii we mostly use the following two tools:

Pingdom
This tool offers good insight in the ‘assets’ that are loaded. Assets are files like images, JavaScript and CSS. Pingdom specifies the loadtime in different phases called connect, send, wait and receive. A nice feature is the sorting of all assets on size, load time and type. The different tabs offer various insights on areas for improvement. The drawback of pingdom is the fact that it is only a snapshot in time without offering reliable data. Worth noting is the fact that pingdom uses no-cache headers, so if you are using a proxy caching solution this will be bypassed by pingdom. Do you want to test your website with pingdom? Follow the steps below:

  • Go to tools.pingdom.com
  • Enter the URL of the webpage you want to test
  • Open the settings menu
  • Choose between making your test public or not
  • Choose the location closest to your target audience
  • Click on the ‘test now’ button

Webpagetest.org

This tool offers much more in the way of customizing your tests. For example you can set the number of repeated tests to increase reliability, you can chose between lots of locations and can compare two sites. Webpagetest offers a quick insight into the main speed factors by offering grades in the top of the report.

Webpagetest Grades

To use webpagetest.org to you site speed, follow the steps below:

  • Go to webpagetest.org
  • Enter the URL of the webpage you want to test
  • Choose the location closest to your target audience
  • Open the ‘advanced settings’ menu
  • Increase the number of tests to 5 or more.
  • Optional: check the box for keeping the test private.
  • Click the ‘start test’ button

How to interpret the results

First & repeat view:

Many tools perform two tests in one: the first and repeat view test. The first view test replicates a situation where a visitor visits your site for the first time.  This means having no cookies or cached assets on their hard drive. A repeat view test replicates a situation where a visitor visits your site for a second time and has stored cookies and assets on their hard drive. Normally a repeat view will be much faster.

Load time – Document Complete:

This is the load time that stops at the moment the browser considers the page loaded. This corresponds roughly with the moment all image, CSS  and JavaScript assets are loaded.

Load-time – Fully Loaded:

This is the load time that stops at the moment there is no network activity anymore. This takes usually more time than document complete. because many JavaScript scripts are only executed after the document is complete. These scripts can load external content such as tracking pixels, cookies, etc.

First Byte time:

This is the time between requesting a page and the moment the first byte of the HTML is received. An important factor when testing site speed. In the meantime the web server has executed PHP functions, has performed database queries and has generated the HTML of the page. In a research published on moz.com a relationship is established between organic ranking and first byte time.

Test Site Speed - First Byte Time vs Organic Ranking

Start render:

The moment the first visual content is visible for your visitors. This metric is very important, nothing is more unwelcoming than a blank page.

Visually complete:

The moment the full page is completely rendered in your browser. This moment is determined by analyzing a video of the rendering of your site.

How to improve your load time

Both pingdom and webpagetest list a number of recommendations. Below you will find two lists, one with things you can do yourself, the second with things that should be taken care of by your web hosting.

Do it yourself

Progressive JPEG’s

By utilizing progressive JPEG’s your JPEG images are already visible in a low resolution before the actual resolution is loaded. Try saving your JPEG’s in the lowest possible quality while they still look good. In Photoshop, choose the option ‘save for web’ and subsequently ‘Progressive JPEG’. In addition you could use the smush.it tool made by Yahoo. There is a WordPress plugin that smushes all your uploaded images. Smush.it will further compress your images in a lossless way.

Use a CDN / Serve static content from a cookieless domain.

At Savvii we have this option built in. By utilizing a Content Delivery Network your browser can download more assets simultaneously. In addition to this a CDN does not set cookies. Both improve the downloading speed of static assets.

Minimize redirects

Each redirect adds to the overall loading time. Try to remove them altogether by making sure the referring hyperlinks contain the correct URL’s in the first place.

Avoid bad requests

This means checking all your assets for 404 not found errors and fixing them. Both pingdom and webpagetest.org show assets with errors.

Hosting

The recommendations below are normally only doable when you are the admin of your own VPS or server. In the case you use managed hosting, contact your hosting company on these recommendations. Quality hosting companies will have these recommendations already implemented on their systems.

Keep-alive enabled:

This is a server setting that makes sure the connection between server and client stays open. Setting up a connection takes time so this is faster thank keep-alive disabled.

Compress Transfer:

This is a very important server setting that makes sure that static text based assets (like html, CSS, javascript) are compressed before they are being sent to the client. Smaller assets are faster transferred.

Compress Images:

Same as above but for image assets.

Cache static content/Leverage browser caching:

This setting defines if and for how long the browser may cache assets from your site. When your browser is not allowed to cache items this leads to longer load times for repeat visits.

In general it is a best practice to remove all unnecessary elements from your website. Sliders are notoriously slow, the same goes for plugins that rely on API’s (twitter, Facebook, etc.). The speed of your website is always the result of the following elements: user, ‘internet’, application and hosting. You do not have influence over the first two but you can surely improve the latter two.

What is fast?

The answer is: it depends. It depends on the person visiting your site. However, some companies have published guidelines for load time. Google says it aims for a load time of 1 sec. for mobile devices. A 2009 research by Forrester (for Akamai) shows that 2 seconds is a good target load time for e-commerce sites on a desktop. You have to worry if your site is 3 sec. or slower because 47% of visitors will leave your site. At Savvii we think 2 sec. for ‘visually complete’ is a minimal load time you should aim for. But important: always test site speed.

Are you curious to see what Savvii can do for your website? Please contact us.

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