Military Time / 24 Hour Clock
The 24-hour clock is a convention of time keeping in which the day runs from midnight to midnight and
is divided into 24 hours indicated by the hours passed since midnight, from 0 to 23. This system is the
most commonly used time notation in the world today, and is the international standard notation for
time of day. In the practice of medicine, the 24-hour clock is generally used in documentation of care as
it prevents any confusion as to when events occurred in a patient's medical history.
In the 24-hour time notation, the day begins at midnight, 00:00, and the last minute of the day begins at
23:59. Where convenient, the notation 24:00 may also be used to refer to midnight at the end of a given
date – that is, 24:00 of one day is the same time as 00:00 of the following day.
Greenwich
1:00 am
2:00 am
3:00 am
4:00 am
5:00 am
6:00 am
7:00 am
8:00 am
9:00 am
10:00 am
11:00 am
12:00 noon
24-Hour clock
01:00
02:00
03:00
04:00
05:00
06:00
07:00
08:00
09:00
10:00
11:00
12:00
Greenwich
1:00 pm
2:00 pm
3:00 pm
4:00 pm
5:00 pm
6:00 pm
7:00 pm
8:00 pm
9:00 pm
10:00 pm
11:00 pm
12:00 midnight
24-Hour clock
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
24:00 or 00:00
Evaluation: Chapter 7, unit 3, The 24- Hour Clock
1. To determine how 8:30 P.M. is expressed in 24-hour clock add 8:30 +____ hours = 20:30
hours
2. Write the correct 24-hour clock times for each for each of the following Greenwich
times.
a.)
b.)
c.)
d.)
e.)
f.)
5:00 a.m. ____
10:30 a.m.____
1:15 p.m. ____
7:00 p.m.____
12.00 midnight ____
12:50 a.m. ____
3. Write the correct Greenwich times for each of the following 24-hour clock times.
a.) 03:30 _____
b.) 10:00 _____
c.) 18:30 _____
d.) 15:30 _____
e.) 00:20 _____
f.) 24:00 _____