In a WordPress Multisite installation, the maximum file size allowed for uploads is limited to only 1500 kilobytes (approx. 1.5 megabytes) by default. This is done to save disk space, but with modern high-quality images, PDF files, or videos, this limit is quickly reached.
Here is how you can change the maximum file size:
Go to the Network Settings from the top-left menu: My Sites > Network Admin > Settings.
Scroll down to the bottom of the page to the Upload Settings section.
Find the field Max upload file size and enter your desired size in kilobytes (KB).
Save the changes at the bottom of the page.
Help with calculating kilobytes (Megabytes to Kilobytes)
Since WordPress exceptionally requests the size in kilobytes, here is a handy list of the most common size limits that you can copy and paste directly into the field:
10 MB =
10240KB25 MB =
25600KB50 MB =
51200KB100 MB =
122880KB (or rounded to100000)128 MB (Seravo's default maximum) =
131072KB
Please note server limitations: The WordPress setting cannot directly bypass the maximum size limit defined at the server level. In Seravo's service, the server-level upper limit (upload_max_filesize) is 128 MB by default.
The server settings cannot be changed by editing the php.ini file. If you need to upload files even larger than this, it is possible to raise the limit using a separate plugin. You can find instructions for this in this article.