See when your day ends, or how many hours a shift really is. Unpaid breaks come off, and shifts past midnight end the next day.
You finish at
18:00
9 h from start to finish, break included
Hours worked is the time from start to finish minus any unpaid break. When the end time is earlier than the start, the shift runs past midnight and ends the next day.
Your finish time is your start time plus the hours you need to work plus the break. Everything is worked out in your browser; nothing you enter is sent anywhere.