Calendars

Items are scheduled within the Gantt chart based on the work schedule outlined in the Calendar. You can select or customize the calendar by clicking the Settings button in the toolbar. The Calendar setting is on the General Configuration screen.

Gantt comes with two predefined calendars: "Standard" (40-hour work week, 9:00-17:00 every workday) and "24 Hour" (all time is marked as working time). Jira administrators can edit the available calendars or create additional calendars by selecting Manage Work Calendars.

Default Calendar

Choose which calendar will be selected by default when new charts are created. Unless you change this setting, the Standard calendar will be used.

Tempo Workload Schemes

If you've connected Structure and Capacity Planner, any workload schemes created in Planner will be available to use as calendars in Gantt.

Adjusting Start Times

By default, calendars based on workload schemes use a 9:00 am start time each day. You can adjust the start times by clicking Edit in the Actions column.

If you enter a start time that is too late in the day to complete the number of working hours specified in the workload scheme, you will receive an error. If you save the calendar with existing errors, the start time for that day will be set to 12:00 am.

If you’re using Planner mode, editing the times in Gantt does not change the workload scheme in Capacity Planner.

Creating and Editing Calendars

Calendar Format

A calendar is defined by a code in JSON format, which sets the working periods for each day of the week and lists exceptions. Details about the JSON format are provided below.

Basic Structure

Every calendar consists either of a week schedule or list of exceptions, or both:

{
  "week": ...,
  "exceptions": ...
}

All calendar definitions should be wrapped in curly braces: { }

Week Schedule

Week schedule is defined by specifying work ranges for every weekday (monday, tuesday, wednesday, thursday, friday, saturday, sunday):

{
  "week": {
      "monday": [
        {
          "start": 900,
          "finish": 1300
        },
        {
          "start": 1400,
          "finish": 1715
        }
      ],
      "tuesday": [
        {
          "start": 900,
          "finish": 1300
        },
        {
          "start": 1400,
          "finish": 1715
        }
      ]
}}

Time is written using HHMM format, where HH is hour (0-24), and MM is minutes. For example: `1730` for 17:30 (5:30 pm) and `930` for 9:30.

You may skip a weekday either by skipping its definition completely or providing an empty list of ranges:

{"monday": []}

Exceptions

Exceptions are defined for exact dates:

Dates are written using YYYYMMDD format, where YYYY is a 4-digit year, MM is a month (1-12), and DD is a day (0-31).

The workPeriods parameter can be empty, which means it is a day off, or it can contain custom start and finish times, which will override the times you have defined in the main scheme.

Hierarchy

You can also organize calendars into a hierarchy via the "Based on" property, so you can create more specific calendars, based on a general calendar ("Standard", for example).

Deleting Calendars

Deleting a calendar cannot be undone! Please be careful when doing so, as it could impact other Gantt charts that are assigned to that calendar.

Example Calendars

Here are some of our most popular calendar examples.

US Federal Holidays Calendar

5-day work week, 8 hours per day, federal holidays for 2025

UK (England and Wales) Holiday Calendar

5-day work week, 8 hours per day, bank holidays for 2025

Germany Holiday Calendar

5-day work week, 8 hours per day, national holidays for 2025