Kids Corner

Time Conversion from 12-hour clock to 24-hour clock

In 12-hour clock the time has three parts.

Hour	Minute	Period
‘_ _’ ( 01 to 12)	‘_ _’ (00 to 59)	am or pm

The hour part and minute part is separated by ‘:’.                    am = ante meridian

                                                                                                      pm = post meridian

Over View:

CASE	12-hour clock	24-hour clock
1	12 : _ _ am	00:_ _
2	_ _ : _ _ am	_ _ : _ _
3	12 : _ _ pm	12 : _ _
4	_ _ : _ _ pm	12:00 +  _ _ : _ _

Explanation with rules and examples

CASE 1: If there is ‘12’ in the hour part and period is ‘am’.

Example:

Suppose the given time is, 

12:45 am         (This time is in 12-hour clock.)

Rule:   To convert the given time, just replace ‘12’ with ‘00’ and remove ‘am’.

i.e. 00:45         (Now given time is in 24-hour clock)

Note:   Minute part will always remain same.

12-hour clock	24-hour clock
12:45 am	00:45

CASE 2: If there is any hour other than 12 in the hour part and period is ‘am’.

Example 1:

Suppose the given time is, 

10:20 am         (This time is in 12-hour clock.)

Rule:   To convert the given time, just remove ‘am’.

i.e. 10:20         ( Now given time is in 24-hour clock)

Note:   Minute part will always remain the same.

            In this case the hour part will remain same.

12-hour clock	24-hour clock
10:20 am	10:20

Example 2:

Suppose the given time is, 

04:10 am         (This time is in 12-hour clock.)

Rule:   To convert the given time, just remove ‘am’.

i.e. 04:10         ( Now given time is in 24-hour clock)

Note:   Minute part will always remain same.

            In this case the hour part will remain same.

12-hour clock	24-hour clock
04:10 am	04:10

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CASE 3: If there is ‘12’ in the hour part and period is ‘pm’.

Example:

Suppose the given time is, 

12:30 pm        (This time is in 12-hour clock.)

Rule:   To convert the given time, just remove ‘pm’.

i.e. 12:30         ( Now given time is in 24-hour clock)

Note:   Minute part will always remain same.

            In this case the hour part will remain same.

12-hour clock	24-hour clock
12:30 pm	12:30

CASE 4: If there is any hour other than 12 in the hour part and period is ‘pm’.

Example 1:

Suppose the given time is, 

07:15 pm                    (This time is in 12-hour clock.)

Rule:   To convert the given time, add 12:00 in the given time and remove ‘pm’.

i.e.       07:15               (Given time)

         + 12:00               (Addition)

            19:15               (Now given time is in 24-hour clock)

Note:   Minute part will always remain same.

12-hour clock	24-hour clock
07:15 pm	19:15

Example 2:

Suppose the given time is, 

11:55 pm        (This time is in 12-hour clock.)

Rule:   To convert the given time, add 12:00 in the given time and remove ‘pm’.

i.e.       11:55               (Given time)

         + 12:00               (Addition)

            23:55               (Now given time is in 24-hour clock)

Note:   Minute part will always remain same.

12-hour clock	24-hour clock
11:55 pm	23:55

“Please inform me if any mistake is found…”