diff --git a/js/app/models/TimeTable.js b/js/app/models/TimeTable.js
index 00cc30a..a693eda 100644
--- a/js/app/models/TimeTable.js
+++ b/js/app/models/TimeTable.js
@@ -46,6 +46,16 @@ Ext.define('amdaModel.Interval', {
 		   return value;
 		   }
 	},
+         {
+            name: 'durationDay',
+            type: 'float',
+            convert: function(value, rec){
+                if (rec.get('stop') && rec.get('start') && (rec.get('stop')-rec.get('start'))>=0) {
+                    return (rec.get('stop') - rec.get('start'))/3600000.0/24.0;
+                }
+            },
+            persist: false
+        },
         {
             name: 'durationHour',
             type: 'float',
--
libgit2 0.21.2