12pm and 12am are the same in 24 hour clock, at 0:00 hours
If you are talking about from 12pm-4pm = 4 hours. If you are talking about from 12am-4pm = 16 hours.
9:12pm plus 8 hours = 5:12am
12am is night time and 12pm is in the day time 12am starts after 11pm,,
12pm is daytime (noon) 12am is nighttime.
Its anything from 12am-12pm.
miday is 12pm midnight is 12am.
After midnight it is 12 am.
Afternoon: 12pm-6pmMorning: 6am-11:59amEvening: 6pm- 8pmNight:8pm-12amLate Night:12am-5:59am
AM = the hours of usual sleep and wake. 1am to 12am. PM = The hours of afternoon, evening, and sleep. 1pm to 12pm, or midnight.
12am to 4pm is 16 hours.