diff --git a/getdates.py b/getdates.py
index 5ad39b9..421cb61 100755
--- a/getdates.py
+++ b/getdates.py
@@ -19,7 +19,7 @@ def dateArgs(argv = sys.argv[1:]):
  mode = 0
 
  for arg in argv:
-  if mode == 0 or (mode == 3 and not isinstance(arg,int)):
+  if mode == 0:
    if arg == "-f":
     mode = 1
    elif arg == "-t":
@@ -30,7 +30,10 @@ def dateArgs(argv = sys.argv[1:]):
     strings += [arg]
     mode = 0
   elif mode == 3:
-   av = arg
+   try:
+    av = int(arg)
+   except ValueError:
+    raise ValueError("Number of days for running average must be an integer.")
    mode = 0
   elif mode == 1:
     fr = getDate(arg)
@@ -44,7 +47,7 @@ def dateArgs(argv = sys.argv[1:]):
 
  if to != None and fr != None and to < fr:
   raise ValueError("From date must be before To date.")
- 
+
  return strings, fr, to, av
     
 
@@ -65,15 +68,43 @@ def dateList(fr, to):
  return [[(fr+datetime.timedelta(days=i)).strftime('%Y-%m-%d')] for i in range((to+datetime.timedelta(days=1)-fr).days)]
 
 
+def avg(list):
+ sum = 0
+
+ for i in list:
+  sum += i
+
+ return int(sum / len(list))
+
+
+def fillAverage(cur, av):
+ vals = []
+ for day in cur:
+  vals = ([day[len(day)-1]] + vals)[:av]
+  day += [avg(vals)]
+ return cur
+
+
 def fillList(db, string, cur, av):
  for day in cur:
   day += list(db.executeQuery(queryBuilder(day[0], string)))[0]
 
+ if not av == 0:
+  cur = fillAverage(cur, av)
+
  return cur
 
 
 def getHeaders(strings, av):
- return [["Date", "Tweets"] + [string for string in strings]]
+ if av == 0:
+  return [["Date", "Tweets"] + [string for string in strings]]
+ 
+ headers = ["Date", "Tweets", "Average"]
+
+ for string in strings:
+  headers += [string, "Average " + string]
+
+ return [headers]
 
 
 def getTweetsByDate(strings = [], fr = None, to = None, av = 0, path = tools.config.dbpath, headers = False):