How do I add two different time together with hour and mins

[arod2773pacbell]

I would like to do a Excel worksheet to add my weekly time. I need the
formula to add 8:30 am and 4:30 pm and the result would be I worked 8 hours
for that day

 

[Aladin Akyurek]

=B1-A1+(B1<A1)

where A1 houses 8:30 AM and B1 4:30 PM.