diff --git a/actionpack/lib/action_view/helpers/number_helper.rb b/actionpack/lib/action_view/helpers/number_helper.rb
index 43122ef2babaf..56a045fec5e8a 100644
--- a/actionpack/lib/action_view/helpers/number_helper.rb
+++ b/actionpack/lib/action_view/helpers/number_helper.rb
@@ -169,6 +169,8 @@ def number_to_currency(number, options = {})
       # * <tt>:delimiter</tt>                   - Sets the thousands delimiter (defaults to "").
       # * <tt>:strip_insignificant_zeros</tt>   - If +true+ removes insignificant zeros after the decimal separator
       #                                           (defaults to +false+).
+      # * <tt>:format</tt>                      - Specifies the format of the percentage string
+      #                                           The number field is <tt>%n</tt> (defaults to "%n%").
       # * <tt>:raise</tt>                       - If true, raises +InvalidNumberError+ when the argument is invalid.
       #
       # ==== Examples
@@ -180,6 +182,7 @@ def number_to_currency(number, options = {})
       #  number_to_percentage(302.24398923423, :precision => 5)           # => 302.24399%
       #  number_to_percentage(1000, :locale => :fr)                       # => 1 000,000%
       #  number_to_percentage("98a")                                      # => 98a%
+      #  number_to_percentage(100, :format => "%n  %")                    # => 100  %
       #
       #  number_to_percentage("98a", :raise => true)                      # => InvalidNumberError
       def number_to_percentage(number, options = {})
@@ -193,13 +196,17 @@ def number_to_percentage(number, options = {})
 
         options = options.reverse_merge(defaults)
 
+        format = options[:format] || "%n%"
+
         begin
-          "#{number_with_precision(number, options.merge(:raise => true))}%".html_safe
+          value = number_with_precision(number, options.merge(:raise => true))
+          format.gsub(/%n/, value).html_safe
         rescue InvalidNumberError => e
           if options[:raise]
             raise
           else
-            e.number.to_s.html_safe? ? "#{e.number}%".html_safe : "#{e.number}%"
+            formatted_number = e.number.to_s.html_safe? ? format.gsub(/%n/, e.number).html_safe : format.gsub(/%n/, e.number)
+            formatted_number.html_safe? ? formatted_number.html_safe : formatted_number
           end
         end
       end
diff --git a/actionpack/lib/action_view/locale/en.yml b/actionpack/lib/action_view/locale/en.yml
index f2a83b92a9233..7cca7d969aaab 100644
--- a/actionpack/lib/action_view/locale/en.yml
+++ b/actionpack/lib/action_view/locale/en.yml
@@ -37,6 +37,7 @@
         # precision:
         # significant: false
         # strip_insignificant_zeros: false
+        format: "%n%"
 
     # Used in number_to_precision()
     precision:
diff --git a/actionpack/test/template/number_helper_test.rb b/actionpack/test/template/number_helper_test.rb
index 8d679aac1d938..ca897a48cca58 100644
--- a/actionpack/test/template/number_helper_test.rb
+++ b/actionpack/test/template/number_helper_test.rb
@@ -57,6 +57,7 @@ def test_number_to_percentage
     assert_equal("1000.000%", number_to_percentage("1000"))
     assert_equal("123.4%", number_to_percentage(123.400, :precision => 3, :strip_insignificant_zeros => true))
     assert_equal("1.000,000%", number_to_percentage(1000, :delimiter => '.', :separator => ','))
+    assert_equal("1000.000  %", number_to_percentage(1000, :format => "%n  %"))
   end
 
   def test_number_with_delimiter