There are total 21 hours or 1260 minutes from 4am to 1am. In words, this duration is equal to twenty-one hours or one thousand two hundred sixty minutes.
How many hours from
| 10AM to 8PM | 3PM to 2AM | 6AM to 4AM |
| 8AM to 3AM | 8PM to 3AM | 9AM to 8AM |
| 9PM to 9AM | 1PM to 9PM | 12PM to 11AM |
| 6AM to 12PM | 7PM to 3PM | 5AM to 3PM |
| 4PM to 1PM | 9AM to 5AM | 9PM to 12PM |
| 8AM to 10PM | 11AM to 4PM | 8AM to 4AM |
