diff --git a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
index 4b8d267b4e..c0efababa9 100644
--- a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
@@ -9,15 +9,11 @@ module ActiveSupport
 
       def convert
         number = self.number.to_s.strip
-        number_f = number.to_f
         format = options[:format]
 
-        if number_f.negative?
-          number = number_f.abs
-
-          unless options[:precision] == 0 && number < 0.5
-            format = options[:negative_format]
-          end
+        if number.sub!(/^-/, "") &&
+           (options[:precision] != 0 || number.to_f > 0.5)
+          format = options[:negative_format]
         end
 
         rounded_number = NumberToRoundedConverter.convert(number, options)
diff --git a/activesupport/test/number_helper_test.rb b/activesupport/test/number_helper_test.rb
index 8b346dd469..579ba73ede 100644
--- a/activesupport/test/number_helper_test.rb
+++ b/activesupport/test/number_helper_test.rb
@@ -79,6 +79,12 @@ module ActiveSupport
           assert_equal("1,234,567,890.50 - K&#269;", number_helper.number_to_currency("-1234567890.50", unit: "K&#269;", format: "%n %u", negative_format: "%n - %u"))
           assert_equal("0.00", number_helper.number_to_currency(+0.0, unit: "", negative_format: "(%n)"))
           assert_equal("$0", number_helper.number_to_currency(-0.456789, precision: 0))
+          assert_equal("$1,11", number_helper.number_to_currency("1,11"))
+          assert_equal("$0,11", number_helper.number_to_currency("0,11"))
+          assert_equal("$,11", number_helper.number_to_currency(",11"))
+          assert_equal("-$1,11", number_helper.number_to_currency("-1,11"))
+          assert_equal("-$0,11", number_helper.number_to_currency("-0,11"))
+          assert_equal("-$,11", number_helper.number_to_currency("-,11"))
         end
       end