Why 10pm to 6am is 8 hours
10:00 PM is 22:00. 6:00 AM the next day is 6:00 plus 24 hours = 30:00. 30 − 22 = 8 hours. Same length as 9 to 5. Then subtract lunch the same way.
FAQ
Does 10pm to 6am count as overnight? Yes. The end is the next calendar day.
Is it 8 hours of pay? Before unpaid breaks, yes. After a 30-minute meal it is 7.50 hours unless your job pays the meal.
What about 11pm to 7am? Also 8 hours before breaks. Use the chip above.