diff --git a/script.rb b/script.rb
index 9e7e7a7..332ee96 100644
--- a/script.rb
+++ b/script.rb
@@ -6,6 +6,7 @@ require 'youtube-dl'
 require 'sequel'
 require 'date'
 require 'optparse'
+require 'filesize'
 
 options={}
 OptionParser.new do |parser|
@@ -13,7 +14,7 @@ OptionParser.new do |parser|
         options[:feed]=feed
     end
 
-    parser.on("-m", "--max-storage SIZE", "Maximum bytes on disk to occupy with videos") do |maxstorage|
+    parser.on("-m", "--max-storage SIZE", "Maximum total size on disk to occupy with videos") do |maxstorage|
         options[:maxstorage]=maxstorage
     end
 
@@ -44,7 +45,7 @@ open(options[:feed]) do |rss|
                       :filesize => File.size("#{video.filename}"),
                       :downloaded => DateTime.now)
         if not options[:maxstorage].empty?
-            while videos.sum(:filesize) > options[:maxstorage].to_i
+            while videos.sum(:filesize) > Filesize.from(options[:maxstorage]).to_i
                 oldest=videos.order(:downloaded).first
                 File.delete(oldest[:filename])
                 videos.where(:id => oldest[:id]).delete