To convert to 12-hour time format:05:15 → 5:15 AM (morning, so AM)21:18 → 9:18 PM (21 minus 12 = 9)00:31 → 12:31 AM (midnight is 12 AM)19:27 → 7:27 PM (19 minus 12 = 7)23:59 → 11:59 PM (almost midnight)In 12-hour time, we use AM for midnight to before noon, and PM for after noon to before midnight.