Since the release of WordPress 5.2, a new tool called "Site Health" is built into WordPress.
Using Site Health, you can check the size of your WordPress directories and database.
First, login to your WordPress Admin Dashboard.
Next, click on Tools and then Site Health.
Click on Info and then the Directories and Sizes tab where you’ll find the following information about your WordPress site:
- WordPress directory size
- Uploads directory size
- Themes directory size
- Plugins directory size
- Database size
- Total installation size
If you're wanting a more detailed view of your plan's disk space, you could install the My Simple Space plugin to display total usage as well as:
- wp-content total size
- wp-content/plugins size
- wp-content/themes size
- wp-content/uploads size
- Database size
- Total available memory/used memory
- PHP Version and OS (32/64 bit)
The My Simple Space plugin cycles through your WordPress install path to calculate the total space used including plugins, themes, upload folders, and also other folders under wp-content.