Updated: January 2018
Your plugin choices affect website speed. But how much plugins affect load time varies from a thousandth of a second – to seconds. A page load time of under 2 seconds is our goal. Half our performance budget is for a theme and plugins. It also includes cloud-based, widgets like Google Analytics, Google Fonts, and Facebook. The other one-second is for branding the site with images.
It’s a common myth that installing too many plugins slows down your site. It isn’t the quantity of plugins that matter – it’s the quality.
The WordPress Plugin Directory now has over 55,000 plugins to choose from. In error, many site owners think the most popular plugins are the wisest choice. This isn’t always true. In fact, from our testing the most-liked plugins are often the slowest loading plugins.
The number of active installs indicates “herd” popularity. The plugin download page tell us what this number is. Or you can click the View Details link on your WordPress dashboard page.
We have many choices of free WordPress plugins that add unique and sometimes esoteric functions. Our rule of thumb is selecting the plugin with the smallest-download package size. The compressed file size is in “k” (kilobytes) or in some cases, “M” (megabytes).
It’s best practice to add functionality into your theme using several small plugins. One fat Swiss-army knife plugin can cause what we call “site drag” – adding delays to your site. Some plugins add drag globally to your entire site even when they’re just used on one page.
For example, Contact Form 7 plugin has over a million installs. Site owners don’t realize this plugin adds three HTTP requests. And 28k page weight to every page on your site – yes, every single page. Even if the shortcode is only used on your contact page – or even not used at all. That may sound small – but in our book, where milliseconds add up to seconds, it isn’t.
For an unknown reason, WordPress doesn’t give compressed plugin size information. You don’t see this number until you actually download from your browser. A proper link would tell the size of a download. That’s good “web etiquette.” WordPress doesn’t think it’s important information (yet). Speed information isn’t high on their agenda. But it is on ours. Any site owner concerned about mobile user experience should pay attention.
When optimizing in a staging area, most online speed tools can’t access these test spaces. So we’ve build prototype pages offsite with the exact same plugins and theme. This helps us establish speed opportunities and pitfalls.
One site under test has 33 active plugins. A few of these plugins improve load time and site optimization. Others add functionality to a responsive, fast-loading theme. Others are for better security. In this case, the theme is “Accelerate.” It’s available at the free WordPress Theme Directory. Most of the default WordPress themes like Twenty-sixteen and Twenty-seventeen are fast loading. Others need speed testing.
Page load time with 33 plugins:
Pingdom to NY: 750 milliseconds.
WebPagetest.org: 1 second.
Tested on a cheap, shared, Linux server.
Mobile WordPress Speed – without coding!