04:21 is 4:21 AM on a 12-hour clock and "04:21 Hours" in Military Time. We use this system throughout the world (not just the military) and leverages a 24-hour time clock rather than the 12-hour AM/PM system known to most English-speaking countries. Below are ways to convert 04:21 through a time chart, automated calculator, and ways to convert by hand.
| 24-hour format | 12-hour format |
|---|---|
| 04:21 | 4:21 AM |
A quick cheatsheet for all time conversions like 4:21 AM. Click the clock. Select your time. We'll highlight the row for the time you choose.
It is easy to convert from 24-hour time to 12-hour time once you know a few tricks. The primary difference between the two is that the hours in a 24-hour clock go all the way up to 23 (from 0 to 23). In a 12-hour clock, the hour resets to 1 after noon (midday). Follow the steps below to convert 04:21 to 12-hour time.
24-hour time is used in aviation, military, meteorology, logistics, and other fields. The 12-hour clock is only used in 18 countries globally, including the United States and Canada. 24-hour time and military time are very similar! See our military time converter for more information.
| 24 Hour Clock | 12 Hour Clock (AM/PM) | Military Time |
|---|---|---|
| 04:21 | 4:21 | 0421 |
| 04:26 | 4:26 | 0426 |
| 04:31 | 4:31 | 0431 |
| 04:36 | 4:36 | 0436 |
| 04:41 | 4:41 | 0441 |
| 04:46 | 4:46 | 0446 |
| 04:51 | 4:51 | 0451 |
| 04:56 | 4:56 | 0456 |
| 05:01 | 5:01 | 0501 |
| 05:06 | 5:06 | 0506 |
| 05:11 | 5:11 | 0511 |
| 05:16 | 5:16 | 0516 |
| 05:21 | 5:21 | 0521 |
| 05:26 | 5:26 | 0526 |
| 05:31 | 5:31 | 0531 |
| 05:36 | 5:36 | 0536 |