Gzip compression is important for website performance as it reduces data size with minimal memory usage. You can achieve compression of between 70% to 90% depending on the data size which leads to improved page load speed.
NOTE: Some web hosting platforms like WPEngine, Kinsta, DreamHost, etc. have Gzip compression enabled by default in their server.
How to check if Gzip compression is enabled
You can use Gzip compression checker tool to find out if Gzip compression is enabled in your blog.
The tool may report that Gzip compression is not enabled even when it is enabled if you are using external URLs with data that is not Gzip compressed. You can either remove the URL or ignore the warning.
How to enable Gzip compression
You can enable Gzip compression by either using a plugin or .htaccess file.
Option 1: Use .htaccess file
If your website is running on Apache Web server, then you can add the code below to .htaccess file to enable gzip compression.
<IfModule mod_deflate.c>
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/vnd.ms-fontobject
AddOutputFilterByType DEFLATE application/x-font
AddOutputFilterByType DEFLATE application/x-font-opentype
AddOutputFilterByType DEFLATE application/x-font-otf
AddOutputFilterByType DEFLATE application/x-font-truetype
AddOutputFilterByType DEFLATE application/x-font-ttf
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE font/opentype
AddOutputFilterByType DEFLATE font/otf
AddOutputFilterByType DEFLATE font/ttf
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE image/x-icon
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/javascript
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/xml
</IfModule>
Option 2: Use a plugin
WordPress cache plugins like WP Super Cache, W3 Total Cache, WP Rocket, WP Fastest Cache, WP-Optimize, etc., have the option to enable Gzip compression.