2 files changed, 5 insertions, 5 deletions
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index a0f610d60c..92b8417150 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -253,7 +253,7 @@ class Time
       :hour => 23,
       :min => 59,
       :sec => 59,
-      :usec => 999999.999
+      :usec => Rational(999999999, 1000)
     )
   end
 
@@ -268,7 +268,7 @@ class Time
     change(
       :min => 59,
       :sec => 59,
-      :usec => 999999.999
+      :usec => Rational(999999999, 1000)
     )
   end
 
@@ -288,7 +288,7 @@ class Time
       :hour => 23,
       :min  => 59,
       :sec  => 59,
-      :usec => 999999.999
+      :usec => Rational(999999999, 1000)
     )
   end
   alias :at_end_of_month :end_of_month
@@ -321,7 +321,7 @@ class Time
       :hour  => 23,
       :min   => 59,
       :sec   => 59,
-      :usec  => 999999.999
+      :usec  => Rational(999999999, 1000)
     )
   end
   alias :at_end_of_year :end_of_year
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index 75fbd98b05..7825283651 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -337,7 +337,7 @@ module ActiveSupport
       end
 
       def transfer_time_values_to_utc_constructor(time)
-        ::Time.utc_time(time.year, time.month, time.day, time.hour, time.min, time.sec, time.respond_to?(:usec) ? time.usec : 0)
+        ::Time.utc_time(time.year, time.month, time.day, time.hour, time.min, time.sec, time.respond_to?(:nsec) ? Rational(time.nsec, 1000) : 0)
       end
 
       def duration_of_variable_length?(obj)