diff --git a/librarian/plugins/diskspace/views/diskspace/_space_info.tpl b/librarian/plugins/diskspace/views/diskspace/_space_info.tpl
index 0302e982..a648ce8c 100644
--- a/librarian/plugins/diskspace/views/diskspace/_space_info.tpl
+++ b/librarian/plugins/diskspace/views/diskspace/_space_info.tpl
@@ -1,7 +1,7 @@
 <%namespace name="widgets" file="../_widgets.tpl"/>
 
 <%def name="space(free, total)">
-<% pct = round(free / total * 100, 1) if total != 0 else 100 %>
+<% pct = round((total - free) / float(total) * 100, 1) if total else 100 %>
 ## Translators, %s is the amount of free space in bytes, KB, MB, etc.
 ${widgets.progress(_('Total space (%s free)') % h.hsize(free), pct)}
 </%def>