diff --git a/app/models/site.rb b/app/models/site.rb
--- a/app/models/site.rb
+++ b/app/models/site.rb
@@ -10,29 +10,23 @@
   end
 
   def time_left
-    contest_time = Configuration['contest.time_limit']
-    if tmatch = /(\d+):(\d+)/.match(contest_time)
-      h = tmatch[1].to_i
-      m = tmatch[2].to_i
-      
-      contest_time = h.hour + m.minute
+    contest_time = Configuration.contest_time_limit
 
-      return contest_time if !self.started
+    return nil if contest_time == nil
+
+    return contest_time if !self.started
 
-      current_time = Time.now.gmtime
-      if self.start_time!=nil
-        finish_time = self.start_time + contest_time
-      else
-        finish_time = current_time + contest_time
-      end
+    current_time = Time.now.gmtime
+    if self.start_time!=nil
+      finish_time = self.start_time + contest_time
+    else
+      finish_time = current_time + contest_time
+    end
 
-      if current_time > finish_time
-        return current_time - current_time
-      else
-        finish_time - current_time 
-      end
+    if current_time > finish_time
+      return current_time - current_time
     else
-      nil
+      return finish_time - current_time 
     end
   end
 
@@ -41,11 +35,9 @@
       return false
     end
 
-    contest_time = Configuration['contest.time_limit']
-    if tmatch = /(\d+):(\d+)/.match(contest_time)
-      h = tmatch[1].to_i
-      m = tmatch[2].to_i
-      return Time.now.gmtime > (self.start_time + h.hour + m.minute)
+    contest_time = Configuration.contest_time_limit
+    if contest_time!=nil
+      return Time.now.gmtime > (self.start_time + contest_time)
     else
       false
     end