Purpose

Users would like the time in Jira to show in the 24 hours format rather than the 12 hours format.

Solution

In order to change this configuration in Jira Server/Data Center you must have the Jira System Administrator global permission. 

You may refer to this page for more information: Changing the Due Date Input Format

1. Go to the General Configuration page of your Jira instance

   • Keyboard shortcut : 'G' + 'G' + Start typing 'General Configuration' and hit Enter.
   • > System > General Configuration
   • or navigate to $JIRAURL/secure/admin/ViewApplicationProperties.jspa

   
   

2. Click on Advance Settings
   

3. To adjust the format for the DateTime picker locate jira.date.* and replace the current value with the value below respectively and click Update :

   jira.date.picker.javascript.format=%e/%b/%y
   jira.date.time.picker.javascript.format=%e/%b/%y %H:%M
   jira.date.time.picker.java.format=dd/MMM/yy HH:mm
   jira.date.picker.java.format=dd/MMM/yy

4. To adjust the format for the display on all other places, go to the Look and Feel page of your Jira instance

   • Keyboard shortcut : 'G' + 'G' + Start typing 'Look and feel' and hit Enter.
   • > System > User Interface > Look and Feel
   • or navigate to $JIRAURL/secure/admin/LookAndFeel!default.jspa

5. Locate the Time Format and replace the current value with the value below and click Update :

   HH:mm

6. Locate the Day Format and replace the current value with the value below and click Update :

   EEEE HH:mm

7. Locate the Complete Date/Time Format and replace the current value with the value below and click Update :

   dd/MMM/yy HH:mm