diff --git a/helpdesk/lib.py b/helpdesk/lib.py
index 2edbaebd..b94eaf50 100644
--- a/helpdesk/lib.py
+++ b/helpdesk/lib.py
@@ -229,5 +229,9 @@ def daily_time_spent_calculation(earliest, latest, open_hours):
     
     day_delta = latest - earliest
 
-    # returns up to 86399 seconds
-    return day_delta.seconds
\ No newline at end of file
+    # returns up to 86399 seconds, add one second if full day
+    time_spent_seconds = day_delta.seconds
+    if time_spent_seconds == 86399:
+        time_spent_seconds += 1
+    
+    return time_spent_seconds
\ No newline at end of file