diff --git a/lib/mastodon/media_cli.rb b/lib/mastodon/media_cli.rb
index 2a4e3e379f3dfa751aa2588a96381ed59995ace4..45181f59e6a94105025b8ac4be7b6edb0f8a0ad8 100644
--- a/lib/mastodon/media_cli.rb
+++ b/lib/mastodon/media_cli.rb
@@ -31,7 +31,7 @@ module Mastodon
       processed, aggregate = parallelize_with_progress(MediaAttachment.cached.where.not(remote_url: '').where('created_at < ?', time_ago)) do |media_attachment|
         next if media_attachment.file.blank?
 
-        size = media_attachment.file_file_size + (media_attachment.thumbnail_file_size || 0)
+        size = (media_attachment.file_file_size || 0) + (media_attachment.thumbnail_file_size || 0)
 
         unless options[:dry_run]
           media_attachment.file.destroy