diff --git a/heat/engine/stack.py b/heat/engine/stack.py
index 9a58bcf66c..b0e3b4a378 100644
--- a/heat/engine/stack.py
+++ b/heat/engine/stack.py
@@ -2099,7 +2099,7 @@ class Stack(collections.Mapping):
         start_time = timeutils.round_to_seconds(self.updated_time or
                                                 self.created_time)
         nowish = timeutils.round_to_seconds(datetime.datetime.utcnow())
-        return (nowish - start_time).seconds
+        return int((nowish - start_time).total_seconds())
 
     def time_remaining(self):
         """Time left before stack times out."""
diff --git a/heat/tests/test_stack.py b/heat/tests/test_stack.py
index 13cd050b56..b0f2cac8b0 100644
--- a/heat/tests/test_stack.py
+++ b/heat/tests/test_stack.py
@@ -118,6 +118,16 @@ class StackTest(common.HeatTestCase):
                                                                  10, 10, 0)
         self.assertEqual(600, self.stack.time_elapsed())
 
+    @mock.patch.object(stack, 'datetime')
+    def test_time_elapsed_negative(self, mock_dt):
+        self.stack = stack.Stack(self.ctx, 'test_stack', self.tmpl)
+        # dummy create time 10:00:00
+        self.stack.created_time = datetime.datetime(2015, 7, 27, 10, 0, 0)
+        # mock utcnow set to 09:59:50 (-10s offset)
+        mock_dt.datetime.utcnow.return_value = datetime.datetime(2015, 7, 27,
+                                                                 9, 59, 50)
+        self.assertEqual(-10, self.stack.time_elapsed())
+
     @mock.patch.object(stack, 'datetime')
     def test_time_elapsed_ms(self, mock_dt):
         self.stack = stack.Stack(self.ctx, 'test_stack', self.tmpl)