diff --git a/Operating System/calculate_time.py b/Operating System/calculate_time.py
new file mode 100644
index 0000000..823d239
--- /dev/null
+++ b/Operating System/calculate_time.py	
@@ -0,0 +1,25 @@
+
+import datetime,time
+
+# Start Time
+starttime = datetime.datetime.now()
+
+#long running
+time.sleep(2)
+
+# Get Total Time
+endtime = datetime.datetime.now()
+print((endtime - starttime).seconds)
+
+# Time Format
+seconds = (endtime - starttime).seconds
+m, s = divmod(seconds, 60)
+h, m = divmod(m, 60)
+print("%02d:%02d:%02d" % (h, m, s))
+
+
+# datetime中的常見類
+#
+#（1）datetime.date 表示日期，常用的屬性有：year, month和day
+#
+#（2）datetime.time 表示時間，常用屬性有：hour, minute, second,