I want to search novels by number of characters

You can search by the number of characters from the search options on the novel search results page.

■ Desktop version:

1. Click on Search options on the search results page.
    
2.  On Search options, click on Character count.
   
3. Select a character count range from the pulldown menu.
   
   * pixiv Premium users can specify any number of characters.
   
4. Click Apply to display search results that match the character count you specified.
   

■ Mobile version:

1. Tap on the Search options icon on the search results page.
   
2. On Search options, click on Character count.
   
3. Select a character count range from the pulldown menu.
   
   * pixiv Premium users can specify any number of characters.
   
4. Tap Apply to display search results that match the character count you specified.