diff --git a/MyTracks/res/values/strings.xml b/MyTracks/res/values/strings.xml
index 051c77225..610f44282 100644
--- a/MyTracks/res/values/strings.xml
+++ b/MyTracks/res/values/strings.xml
@@ -2115,7 +2115,7 @@ limitations under the License.
     translation_description="In the 'Stats' page, the calorie burned.
     
       Character limit: ~23 (1 line)">
-    Calorie expediture
+    Calorie expenditure
   </string>
   <string name="stats_fastest_pace"
     translation_description="In the 'Stats' page, the fastest pace.">
@@ -2382,6 +2382,10 @@ limitations under the License.
     translation_description="Abbreviation for minutes per mile. E.g., '5 min/mi'.">
     min/mi
   </string>
+  <string name="unit_calorie"
+    translation_description="Abbreviation for calorie. E.g., '5 Cal'.">
+    Cal
+  </string>
 
   <!-- Value -->
   <string name="value_adapt_accuracy"
diff --git a/MyTracks/src/com/google/android/apps/mytracks/content/MyTracksProvider.java b/MyTracks/src/com/google/android/apps/mytracks/content/MyTracksProvider.java
index 61030e4fa..0b4f877f7 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/content/MyTracksProvider.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/content/MyTracksProvider.java
@@ -49,7 +49,7 @@ import java.util.ArrayList;
 public class MyTracksProvider extends ContentProvider {
 
   private static final String TAG = MyTracksProvider.class.getSimpleName();
-  private static final int DATABASE_VERSION = 23;
+  private static final int DATABASE_VERSION = 22;
 
   @VisibleForTesting
   static final String DATABASE_NAME = "mytracks.db";
@@ -129,9 +129,6 @@ public class MyTracksProvider extends ContentProvider {
           Log.w(TAG, "Upgrade DB: Adding photo url column.");
           db.execSQL("ALTER TABLE " + WaypointsColumns.TABLE_NAME + " ADD " + WaypointsColumns.PHOTOURL
               + " STRING");
-        }
-        
-        if (oldVersion <= 22) {
           Log.w(TAG, "Upgrade DB: Adding track calorie column.");
           db.execSQL("ALTER TABLE " + TracksColumns.TABLE_NAME + " ADD " + TracksColumns.CALORIE
               + " INTEGER");
diff --git a/MyTracks/src/com/google/android/apps/mytracks/stats/TripStatisticsUpdater.java b/MyTracks/src/com/google/android/apps/mytracks/stats/TripStatisticsUpdater.java
index 677c46ef9..2c5ede91f 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/stats/TripStatisticsUpdater.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/stats/TripStatisticsUpdater.java
@@ -94,7 +94,7 @@ public class TripStatisticsUpdater {
   // A buffer of the recent speed readings (m/s) for calculating max speed
   private final DoubleBuffer speedBuffer = new DoubleBuffer(SPEED_SMOOTHING_FACTOR);
 
-  // Average weight.
+  // Default weight, in kilogram
   private int defaultWeight = 65;
   
   /**
diff --git a/MyTracks/src/com/google/android/apps/mytracks/util/CalorieUtils.java b/MyTracks/src/com/google/android/apps/mytracks/util/CalorieUtils.java
index 0af8f7e00..be43f9e69 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/util/CalorieUtils.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/util/CalorieUtils.java
@@ -40,30 +40,33 @@ public class CalorieUtils {
   private static final double L_TO_KCAL = 5;
 
   /**
-   * Critical speed running in meters per minute. Changes 4.5 miles per hour to
-   * meters per minute.
+   * Critical speed running in meters per minute. Converts 4.5 miles per hour to
+   * meters per minute. 4 miles per hour is regarded as the max speed of walking
+   * and 5 miles per hour is regarded as the minimal speed of running, so we use
+   * the 4.5 miles per hour as the critical seed. <a href=
+   * "http://www.ideafit.com/fitness-library/calculating-caloric-expenditure-0"
+   * >Reference</a>
    */
   @VisibleForTesting
   static final double CRTICAL_SPEED_RUNNING = 4.5 * UnitConversions.MI_TO_KM
-      * UnitConversions.KM_TO_M * UnitConversions.MIN_TO_HR;
+      * UnitConversions.KM_TO_M / UnitConversions.HR_TO_MIN;
 
   public enum ActivityType {
     CYCLING, FOOT
   }
 
   /**
-   * Calculates the calorie of walking. This equation is appropriate
-   * for fairly slow speed ranges—from 1.9 to approximately 4 miles per hour
-   * (mph).
+   * Calculates the calorie of walking. This equation is appropriate for fairly
+   * slow speed ranges—from 1.9 to approximately 4 miles per hour (mph).
    * 
    * @param speed is calculated in meters per second (m/s)
    * @param grade
    * @return the VO2 value in ml/kg/min.
    */
   @VisibleForTesting
-  static double calculateWalkingVO2(double speed, double grade) {
+  static double calculateWalkingVo2(double speed, double grade) {
     // Change meters per second to meters per minute
-    speed *= UnitConversions.MIN_TO_SECOND;
+    speed = speed / UnitConversions.S_TO_MIN;
     /*
      * 0.1 means oxygen cost per meter of moving each kilogram (kg) of body
      * weight while walking (horizontally). 1.8 means oxygen cost per meter of
@@ -73,18 +76,18 @@ public class CalorieUtils {
   }
 
   /**
-   * Calculates the calorie of running. This equation is appropriate
-   * for speeds greater than 5.0 mph (or 3.0 mph or greater if the subject is
-   * truly jogging).
+   * Calculates the calorie of running. This equation is appropriate for speeds
+   * greater than 5.0 mph (or 3.0 mph or greater if the subject is truly
+   * jogging).
    * 
    * @param speed is calculated in meters per second (m/s)
    * @param grade
    * @return the VO2 value in ml/kg/min.
    */
   @VisibleForTesting
-  static double calculateRunningVO2(double speed, double grade) {
+  static double calculateRunningVo2(double speed, double grade) {
     // Change meters per second to meters per minute
-    speed *= UnitConversions.MIN_TO_SECOND;
+    speed *= UnitConversions.MIN_TO_S;
     /*
      * 0.2 means oxygen cost per meter of moving each kg of body weight while
      * running (horizontally). 0.9 means oxygen cost per meter of moving total
@@ -111,7 +114,7 @@ public class CalorieUtils {
    * 
    * @param speed is calculated in meters per second (m/s)
    * @param grade the grade to calculate
-   * @param weight of rider plus bike
+   * @param weight of rider plus bike, in kilogram
    * @param timeUsed how many times used in second
    * @return the power value watts(Joule/second).
    */
@@ -125,7 +128,7 @@ public class CalorieUtils {
     // Lumped constant for aerodynamic drag
     double K2 = 0.185;
 
-    // Get the Power
+    // Get the Power, the unit is Watt (Joule/second)
     double power = earthGravity * weight * speed * (K1 + grade) + K2 * (speed * speed * speed);
 
     // Get the calories
@@ -138,7 +141,7 @@ public class CalorieUtils {
    * @param start the start location
    * @param stop the stop location
    * @param grade the grade to calculate
-   * @param weight the weight of user
+   * @param weight the weight of user, in kilogram
    * @return the calories expenditure between the start and stop location.
    */
   @VisibleForTesting
@@ -160,19 +163,22 @@ public class CalorieUtils {
    * @param start the start location
    * @param stop the stop location
    * @param grade the grade to calculate
-   * @param weight the weight of user
-   * @return the calories expenditure between the start and stop location.
+   * @param weight the weight of user, in kilogram
+   * @return the calories expenditure between the start and stop location, in
+   *         calories.
    */
   @VisibleForTesting
   static double calculateExpenditureFoot(Location start, Location stop, double grade, int weight) {
     // Get speed in meters per second
     double averageSpeed = (start.getSpeed() + stop.getSpeed()) / 2.0;
     // Get VO2 in mL/kg/min
-    double VO2 = getVO2(averageSpeed, grade);
+    double vo2 = getVo2(averageSpeed, grade);
     // Minutes
-    double time = (double) (stop.getTime() - start.getTime()) * UnitConversions.MS_TO_S * UnitConversions.S_TO_MIN;
-    // Get the calorie. The unit of calorie is kcal which is came from mL/kg/min * min * L/mL * kg * kcal/L
-    return VO2 * time * UnitConversions.ML_TO_L * weight * L_TO_KCAL;
+    double time = (double) (stop.getTime() - start.getTime()) * UnitConversions.MS_TO_S
+        * UnitConversions.S_TO_MIN;
+    // Get the calorie. The unit of calorie is kcal which is came from mL/kg/min
+    // * min * kg * L/mL * kcal/L
+    return vo2 * time * weight * UnitConversions.ML_TO_L * L_TO_KCAL;
   }
 
   /**
@@ -183,12 +189,12 @@ public class CalorieUtils {
    * @return the VO2 value.
    */
   @VisibleForTesting
-  static double getVO2(double speed, double grade) {
+  static double getVo2(double speed, double grade) {
     if (grade < 0) {
       grade = 0.0;
     }
 
-    return speed > CRTICAL_SPEED_RUNNING ? calculateRunningVO2(speed, grade) : calculateWalkingVO2(
+    return speed > CRTICAL_SPEED_RUNNING ? calculateRunningVo2(speed, grade) : calculateWalkingVo2(
         speed, grade);
   }
 
diff --git a/MyTracks/src/com/google/android/apps/mytracks/util/StatsUtils.java b/MyTracks/src/com/google/android/apps/mytracks/util/StatsUtils.java
index 760518662..acd2123a5 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/util/StatsUtils.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/util/StatsUtils.java
@@ -40,9 +40,6 @@ public class StatsUtils {
   private static final String GRADE_FORMAT = "%1$d";
   private static final String CALORIES_FORMAT = "%1$.0f";
   
-  private static final String CALORIES_UNIT = "Cal";
-
-  
   private StatsUtils() {}
 
   /**
@@ -334,6 +331,6 @@ public class StatsUtils {
    */
   private static void setCalorie(Activity activity, int itemId, int labelId, double calorie) {
     setItem(activity, itemId, labelId,
-        String.format(Locale.getDefault(), CALORIES_FORMAT, calorie), CALORIES_UNIT);
+        String.format(Locale.getDefault(), CALORIES_FORMAT, calorie), activity.getString(R.string.unit_calorie));
   }
 }
\ No newline at end of file
diff --git a/MyTracks/src/com/google/android/apps/mytracks/util/UnitConversions.java b/MyTracks/src/com/google/android/apps/mytracks/util/UnitConversions.java
index de6453120..3ff534cb7 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/util/UnitConversions.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/util/UnitConversions.java
@@ -22,22 +22,25 @@ package com.google.android.apps.mytracks.util;
  */
 public class UnitConversions {
 
+  private UnitConversions() {}
+
   // Milliliter to liter
-  static final double ML_TO_L = 1 / 1000.0;
+  public static final double ML_TO_L = 1 / 1000.0;
 
   // Millisecond to second
-  static final double MS_TO_S = 1 / 1000.0;
+  public static final double MS_TO_S = 1 / 1000.0;
 
   // Minute to second
-  static final double MIN_TO_SECOND = 60.0;
+  public static final double MIN_TO_S = 60.0;
 
   // Second to minute
-  static final double S_TO_MIN = 1 / MIN_TO_SECOND;
+  public static final double S_TO_MIN = 1 / MIN_TO_S;
 
   // Minute to hour
-  static final double MIN_TO_HR = 1 / 60.0;
+  public static final double HR_TO_MIN = 60.0;
 
-  private UnitConversions() {}
+  // Minute to hour
+  public static final double MIN_TO_HR = 1 / HR_TO_MIN;
 
   // multiplication factor to convert kilometers to miles
   public static final double KM_TO_MI = 0.621371192;
diff --git a/MyTracksLib/src/com/google/android/apps/mytracks/stats/TripStatistics.java b/MyTracksLib/src/com/google/android/apps/mytracks/stats/TripStatistics.java
index 144182363..6ffaefee3 100644
--- a/MyTracksLib/src/com/google/android/apps/mytracks/stats/TripStatistics.java
+++ b/MyTracksLib/src/com/google/android/apps/mytracks/stats/TripStatistics.java
@@ -575,12 +575,13 @@ public class TripStatistics implements Parcelable {
   /**
    * Adds calorie value.
    * 
-   * @param calorieAdded add the value to the total calorie
+   * @param calorie add the value to the total calorie
    */
-  public void addCalorie(double calorieAdded) {
-    this.calorie += calorieAdded;
+  @SuppressWarnings("hiding")
+  public void addCalorie(double calorie) {
+    this.calorie += calorie;
   }
-  
+
   /**
    * Sets calorie value.
    * 
diff --git a/MyTracksTest/src/com/google/android/apps/mytracks/util/CalorieUtilsTest.java b/MyTracksTest/src/com/google/android/apps/mytracks/util/CalorieUtilsTest.java
index 52c820a08..85cb36ec2 100644
--- a/MyTracksTest/src/com/google/android/apps/mytracks/util/CalorieUtilsTest.java
+++ b/MyTracksTest/src/com/google/android/apps/mytracks/util/CalorieUtilsTest.java
@@ -76,8 +76,8 @@ public class CalorieUtilsTest extends TestCase {
    * Checks using running VO2 equation.
    */
   public void testGetVO2_running() {
-    double actual = CalorieUtils.getVO2(CalorieUtils.CRTICAL_SPEED_RUNNING * 2, grade);
-    double expected = CalorieUtils.calculateRunningVO2(CalorieUtils.CRTICAL_SPEED_RUNNING * 2,
+    double actual = CalorieUtils.getVo2(CalorieUtils.CRTICAL_SPEED_RUNNING * 2, grade);
+    double expected = CalorieUtils.calculateRunningVo2(CalorieUtils.CRTICAL_SPEED_RUNNING * 2,
         grade);
     assertEquals(expected, actual);
   }
@@ -89,8 +89,8 @@ public class CalorieUtilsTest extends TestCase {
     // Test at half the critical speed
     double footSpeed = CalorieUtils.CRTICAL_SPEED_RUNNING / 2.0;
 
-    double actual = CalorieUtils.getVO2(footSpeed, grade);
-    double expected = CalorieUtils.calculateWalkingVO2(footSpeed, grade);
+    double actual = CalorieUtils.getVo2(footSpeed, grade);
+    double expected = CalorieUtils.calculateWalkingVo2(footSpeed, grade);
     assertEquals(expected, actual);
   }