diff --git a/astrid/plugin-src/com/todoroo/astrid/core/LabsPreferences.java b/astrid/plugin-src/com/todoroo/astrid/core/LabsPreferences.java
index faccf1913..7cad199fa 100644
--- a/astrid/plugin-src/com/todoroo/astrid/core/LabsPreferences.java
+++ b/astrid/plugin-src/com/todoroo/astrid/core/LabsPreferences.java
@@ -55,6 +55,8 @@ public class LabsPreferences extends TodorooPreferenceActivity {
         } else if (r.getString(R.string.p_third_party_addons).equals(key)) {
             setEnabledSummary(preference, value,
                     R.string.EPr_third_party_addons_desc_enabled, R.string.EPr_third_party_addons_desc_disabled);
+        } else if (r.getString(R.string.p_end_at_deadline).equals(key)){
+            setEnabledSummary(preference, value, R.string.EPr_cal_start_at_due_time, R.string.EPr_cal_end_at_due_time);
         } else if (r.getString(R.string.p_ideas_tab_enabled).equals(key)) {
             if (!Constants.MARKET_STRATEGY.allowIdeasTab()) {
                 PreferenceScreen screen = getPreferenceScreen();
diff --git a/astrid/plugin-src/com/todoroo/astrid/gcal/GCalHelper.java b/astrid/plugin-src/com/todoroo/astrid/gcal/GCalHelper.java
index b6f57a156..525bcb2f8 100644
--- a/astrid/plugin-src/com/todoroo/astrid/gcal/GCalHelper.java
+++ b/astrid/plugin-src/com/todoroo/astrid/gcal/GCalHelper.java
@@ -181,8 +181,13 @@ public class GCalHelper {
                 long estimatedTime = task.getValue(Task.ESTIMATED_SECONDS)  * 1000;
                 if(estimatedTime <= 0)
                     estimatedTime = DEFAULT_CAL_TIME;
-                values.put("dtstart", dueDate - estimatedTime);
-                values.put("dtend", dueDate);
+                if (Preferences.getBoolean(R.string.p_end_at_deadline, true)) {
+                    values.put("dtstart", dueDate);
+                    values.put("dtend", dueDate + estimatedTime);
+                }else{
+                    values.put("dtstart", dueDate - estimatedTime);
+                    values.put("dtend", dueDate);
+                }
                 // setting a duetime to a previously timeless event requires explicitly setting allDay=0
                 values.put("allDay", "0");
                 values.put("eventTimezone", TimeZone.getDefault().getID());
diff --git a/astrid/res/values/keys.xml b/astrid/res/values/keys.xml
index 891fd7899..5347a322a 100644
--- a/astrid/res/values/keys.xml
+++ b/astrid/res/values/keys.xml
@@ -305,6 +305,9 @@
   <!-- use new contact picker setting -->
   <string name="p_use_contact_picker">p_use_contact_picker</string>
   
+  <!-- on calendar end at dealline if true, start at deadline if false -->
+  <string name="p_end_at_deadline">p_end_at_deadline</string>
+  
   <string-array name="EPr_default_addtocalendar_values">
     <!-- addtocalendar: labels that map EPr_default_addtocalendar items to calendar selection in settings. -->
     <item>-1</item>
diff --git a/astrid/res/values/strings-core.xml b/astrid/res/values/strings-core.xml
index 64ce8c49a..378188a0f 100644
--- a/astrid/res/values/strings-core.xml
+++ b/astrid/res/values/strings-core.xml
@@ -647,6 +647,12 @@
   <string name="EPr_ideas_tab_enabled">Task Ideas</string>
   <string name="EPr_ideas_tab_description">Get ideas to help you complete tasks</string>
   
+  <!-- Preferences: calendar event start time -->
+  <string name = "EPr_cal_end_or_start_at_due_time">Calendar event time</string>
+  <string name = "EPr_cal_end_at_due_time">End calendar events at due time</string>
+  <string name = "EPr_cal_start_at_due_time">Start calendar events at due time</string>
+  
+  
   <string name="EPr_swipe_lists_restart_alert">You will need to restart Astrid for this change to take effect</string>
   
   <string-array name="EPr_swipe_lists_performance_mode">
@@ -656,6 +662,7 @@
       <item>High Performance</item>
   </string-array>
   
+  
   <string-array name="EPr_swipe_lists_performance_desc">
   <!-- slide 49a -->
       <item>Swipe between lists is disabled</item>
diff --git a/astrid/res/xml/preferences_labs.xml b/astrid/res/xml/preferences_labs.xml
index 27aaff9ec..46b20fbd2 100644
--- a/astrid/res/xml/preferences_labs.xml
+++ b/astrid/res/xml/preferences_labs.xml
@@ -22,4 +22,8 @@
         android:key="@string/p_ideas_tab_enabled"
         android:title="@string/EPr_ideas_tab_enabled" 
         android:summary="@string/EPr_ideas_tab_description" />
+    <CheckBoxPreference
+        android:title="@string/EPr_cal_end_or_start_at_due_time"
+        android:key = "@string/p_end_at_deadline" />
+    
 </PreferenceScreen>
diff --git a/astrid/src/com/todoroo/astrid/service/abtesting/ABTests.java b/astrid/src/com/todoroo/astrid/service/abtesting/ABTests.java
index d0f2dfba3..a8327c810 100644
--- a/astrid/src/com/todoroo/astrid/service/abtesting/ABTests.java
+++ b/astrid/src/com/todoroo/astrid/service/abtesting/ABTests.java
@@ -114,7 +114,10 @@ public class ABTests {
         bundles.put(testKey, bundle);
     }
 
-    private void initialize() { // Set up
+    public static final String AB_TEST_CAL_KEY = "cal_ab_test"; //$NON-NLS-1$
 
+    private void initialize() {
+        addTest(AB_TEST_CAL_KEY, new int[] {1, 1}, new int[] {1, 1},
+                new String[] {"end-at-due-time", "start-at-due-time"}); //$NON-NLS-1$ //$NON-NLS-2$
     }
 }
diff --git a/astrid/src/com/todoroo/astrid/utility/AstridPreferences.java b/astrid/src/com/todoroo/astrid/utility/AstridPreferences.java
index 9add885af..f69221f68 100644
--- a/astrid/src/com/todoroo/astrid/utility/AstridPreferences.java
+++ b/astrid/src/com/todoroo/astrid/utility/AstridPreferences.java
@@ -15,6 +15,8 @@ import com.todoroo.astrid.core.PluginServices;
 import com.todoroo.astrid.data.Task;
 import com.todoroo.astrid.data.User;
 import com.todoroo.astrid.service.ThemeService;
+import com.todoroo.astrid.service.abtesting.ABChooser;
+import com.todoroo.astrid.service.abtesting.ABTests;
 
 public class AstridPreferences {
 
@@ -57,6 +59,8 @@ public class AstridPreferences {
 
         Preferences.setIfUnset(prefs, editor, r, R.string.p_third_party_addons, false);
         Preferences.setIfUnset(prefs, editor, r, R.string.p_ideas_tab_enabled, true);
+        Preferences.setIfUnset(prefs, editor, r, R.string.p_end_at_deadline,
+                ABChooser.readChoiceForTest(ABTests.AB_TEST_CAL_KEY) != 0);
 
         if ("white-blue".equals(Preferences.getStringValue(R.string.p_theme))) { //$NON-NLS-1$ migrate from when white-blue wasn't the default
             Preferences.setString(R.string.p_theme, ThemeService.THEME_WHITE);