Automate start date calculation in Jira with due date and original estimate

Summary

You use both the Original Estimate and Due Date fields on Jira work items, and want to automatically set the Start Date field based on the difference between their values. We'll create an automation rule in Jira that calculates the Start Date by subtracting the Original Estimate from the Due Date and triggers when the 'Original Estimate' field is changed.

Solution

Create a Start Date calculation Rule

1. Navigate to Project settings > Automation > Create Rule

2. Choose the Field Value Changed trigger

   • Configure it to trigger when the Time Tracking field changes

3. Add a Smart values condition:

   • First value: fieldChange.field

   • Contains

   • Second value: estimate

4. Add a Create Variable action

   • Variable name: originalEstimateInDays

   • Variable value: {{issue.timetracking.originalEstimateSeconds.divide(28800)}}

     • This converts the original estimate from seconds to days (assuming an 8-hour workday)

5. Add an Edit work item action

   • Set the Start Date field to the smart value: {{issue.duedate.minusBusinessDays(originalEstimateInDays.asNumber)}}

   • This formula subtracts the original estimate (in days) from the due date to calculate the start date and uses the minusBusinessDays() function to include weekdays but not weekends