calculate end time

hello

I need help in how to calculate the end time.

I have the following 2 fields
Start_time
Duration (in minutes)

now i need to calculate at what time did the service end based on the start time and duration of the service

thanks for your help

is it a datetime field or only a time field.
if only time how do you indicate when something ends on the next day?
generally though you can use dateadd()

DATEADD('n',{table.duration},{table.start_time})

The duration will usually be between 20 minutes to 4 hours (in minutes) and will not go into a different date.

what is the data type of Start_time?
Duration is a number/int field type?