How Scheduled End Date Is Calculated in a Salesforce Field Service Multi-Day Service Appointment

How Scheduled End Is Calculated

In Salesforce Field Service, Scheduled End is calculated by adding the Duration to the Scheduled Start, factoring in the service resource's operating hours and recorded absences

Scheduled End − Scheduled Start = Estimated Duration

The Scheduled End field represents the time at which the Service Appointment is scheduled to end. If you are using the Field Service Lightning (FSL) managed package with the scheduling optimizer, this field is populated once the appointment is assigned to a resource.

Operating hours defined for Service Resources are used when calculating the Scheduled End date.

https://help.salesforce.com/articleView?id=pfs_optimization_theory_work_rules_match_time.htm&type=0

Real-Life Example: Engineer Calendar Scenario

Engineer Calendar -> 5:00 - 13:00
New changes->
Scheduled start:30/03/2023 9:30
Scheduled End:30/03/2023 15:30
Duration: 6 hours

After saving, the Scheduled End auto-updates to: 31/03/2023 07:30

Why? The resource's working hours end at 13:00. The appointment starts at 09:30, so the resource can only work 3.5 hours on 30/03 (up to 13:00). The remaining 2.5 hours carry over to the next working day, which starts at 05:00. Adding 2.5 hours to 05:00 gives a Scheduled End of 07:30 on 31/03/2023.

Note: If you update only the Scheduled End field directly (without changing Scheduled Start or Duration), the auto-recalculation does not trigger — the manually entered value is retained.