diff --git a/assets/javascripts/models/doc.coffee b/assets/javascripts/models/doc.coffee
index 59accfee..bb67a672 100644
--- a/assets/javascripts/models/doc.coffee
+++ b/assets/javascripts/models/doc.coffee
@@ -1,5 +1,5 @@
 class app.models.Doc extends app.Model
-  # Attributes: name, slug, type, version, index_path, db_path, mtime
+  # Attributes: name, slug, type, version, index_path, db_path, db_size, mtime
 
   constructor: ->
     super
diff --git a/lib/docs/core/manifest.rb b/lib/docs/core/manifest.rb
index 23f27bdb..5a00a102 100644
--- a/lib/docs/core/manifest.rb
+++ b/lib/docs/core/manifest.rb
@@ -16,6 +16,7 @@ module Docs
     def as_json
       indexed_docs.map(&:as_json).each do |json|
         json[:mtime] = doc_mtime(json)
+        json[:db_size] = doc_db_size(json)
       end
     end
 
@@ -34,5 +35,9 @@ module Docs
     def doc_mtime(doc)
       [@store.mtime(doc[:index_path]).to_i, @store.mtime(doc[:db_path]).to_i].max
     end
+
+    def doc_db_size(doc)
+      @store.size(doc[:db_path])
+    end
   end
 end
diff --git a/test/lib/docs/core/manifest_test.rb b/test/lib/docs/core/manifest_test.rb
index f5045c55..1138b9c6 100644
--- a/test/lib/docs/core/manifest_test.rb
+++ b/test/lib/docs/core/manifest_test.rb
@@ -78,6 +78,11 @@ class ManifestTest < MiniTest::Spec
         mtime_index, mtime_db = mtime_db, mtime_index
         assert_equal mtime_db.to_i, manifest.as_json.first[:mtime]
       end
+
+      it "adds a :db_size attribute" do
+        stub(store).size(db_path) { 42 }
+        assert_equal 42, manifest.as_json.first[:db_size]
+      end
     end
 
     context "when the doc doesn't have an index" do