diff --git a/lib/redmine/views/labelled_form_builder.rb b/lib/redmine/views/labelled_form_builder.rb
index 2b9c2b510..5d29c0977 100644
--- a/lib/redmine/views/labelled_form_builder.rb
+++ b/lib/redmine/views/labelled_form_builder.rb
@@ -50,8 +50,10 @@ class Redmine::Views::LabelledFormBuilder < ActionView::Helpers::FormBuilder
   def hours_field(field, options={})
     # display the value before type cast when the entered value is not valid
     if @object.errors[field].blank?
+      # show the placeholder only when the time span format is "minutes"
+      placeholder = Setting.timespan_format == 'minutes' ? 'h:mm' : nil
       options = options.merge(:value => format_hours(@object.send field))
-                       .with_defaults(:placeholder => 'h:mm')
+                       .with_defaults(:placeholder => placeholder)
     end
     text_field field, options
   end
diff --git a/test/unit/lib/redmine/views/labelled_form_builder_test.rb b/test/unit/lib/redmine/views/labelled_form_builder_test.rb
index 11c3409a2..28d51a3d0 100644
--- a/test/unit/lib/redmine/views/labelled_form_builder_test.rb
+++ b/test/unit/lib/redmine/views/labelled_form_builder_test.rb
@@ -32,10 +32,25 @@ class Redmine::Views::LabelledFormBuilderTest < Redmine::HelperTest
     entry = TimeEntry.new(:hours => '2.5')
     entry.validate
 
-    labelled_form_for(entry) do |f|
-      field_html = f.hours_field(:hours)
-      assert_include 'value="2:30"', field_html
-      assert_include 'placeholder="h:mm"', field_html
+    with_settings :timespan_format => 'minutes' do
+      labelled_form_for(entry) do |f|
+        field_html = f.hours_field(:hours)
+        assert_include 'value="2:30"', field_html
+        assert_include 'placeholder="h:mm"', field_html
+      end
+    end
+  end
+
+  def test_hours_field_should_not_have_placeholder_if_timespan_format_is_decimal
+    entry = TimeEntry.new(:hours => '2.5')
+    entry.validate
+
+    with_settings :timespan_format => 'decimal' do
+      labelled_form_for(entry) do |f|
+        field_html = f.hours_field(:hours)
+        assert_include 'value="2.50"', field_html
+        assert_not_include 'placeholder', field_html
+      end
     end
   end