diff --git a/app/models/project_statistics.rb b/app/models/project_statistics.rb
index 2270ac750716afcbf25c17ee484cfa5bbee0d953..06abd4065239a8c60de134f463042cea1bb1642a 100644
--- a/app/models/project_statistics.rb
+++ b/app/models/project_statistics.rb
@@ -25,8 +25,9 @@ class ProjectStatistics < ActiveRecord::Base
     self.commit_count = project.repository.commit_count
   end
 
+  # Repository#size needs to be converted from MB to Byte.
   def update_repository_size
-    self.repository_size = project.repository.size
+    self.repository_size = project.repository.size * 1.megabyte
   end
 
   def update_lfs_objects_size
diff --git a/changelogs/unreleased/26773-fix-project-statistics-repository-size.yml b/changelogs/unreleased/26773-fix-project-statistics-repository-size.yml
new file mode 100644
index 0000000000000000000000000000000000000000..8ce9bbcb3a995912ce4ac51043c6a157ca26d687
--- /dev/null
+++ b/changelogs/unreleased/26773-fix-project-statistics-repository-size.yml
@@ -0,0 +1,4 @@
+---
+title: Adjust ProjectStatistic#repository_size with values saved as MB
+merge_request: 8616
+author:
diff --git a/spec/models/project_statistics_spec.rb b/spec/models/project_statistics_spec.rb
index 77403cc9eb0ef6b692c424096310a6b85f3027da..ff29f6f66ba425019d87f9ab019f9b5fef803a91 100644
--- a/spec/models/project_statistics_spec.rb
+++ b/spec/models/project_statistics_spec.rb
@@ -107,7 +107,7 @@ describe ProjectStatistics, models: true do
 
   describe '#update_repository_size' do
     before do
-      allow(project.repository).to receive(:size).and_return(12.megabytes)
+      allow(project.repository).to receive(:size).and_return(12)
       statistics.update_repository_size
     end