Describe time in 24-hour format

• A day has 24 hours
• The day starts at 00:00 (midnight)
• Noon is 12:00
• After noon, we add 12 to the hour number

For morning times (12:00 midnight to 11:59 am):

Keep the same hour. Add a zero in front if the hour is a single digit.

For afternoon and night times (12:00 noon to 11:59 pm):

Add 12 to the hour number.

For times from 0000 to 1159:

These are morning times. Remove the first zero if there is one, and add "am".

For times from 1200 to 2359:

These are afternoon or night times. Subtract 12 from the hour, and add "pm".

Example 1: Write 3:47 pm in 24-hour format

Step 1: The hour is 3, and it is pm, so add 12. Step 2: 3 + 12 = 15 Step 3: Keep the minutes the same: 47

Answer: 1547 hours

Example 2: Write 0830 hours in 12-hour format

Step 1: The hour is 08, which is less than 12. Step 2: This is a morning time, so add "am". Step 3: Remove the zero in front: 8

Answer: 8:30 am

Example 3: Write 10:45 pm in 24-hour format

Step 1: The hour is 10, and it is pm. Step 2: Add 12: 10 + 12 = 22 Step 3: Keep the minutes: 45

Answer: 2245 hours

• a.m. means "before noon" (morning: midnight to 11:59 am)
• p.m. means "after noon" (afternoon and night: 12:00 noon to 11:59 pm)
• In 24-hour format, we say "hours" after the number (for example, "fifteen forty-five hours")

Change these times to 24-hour format:

1. 7:00 am → __________
2. 2:00 pm → __________
3. 11:00 am → __________
4. 6:30 pm → __________

Change these times to 12-hour format:

5. 0615 hours → __________
6. 1400 hours → __________
7. 2150 hours → __________

In Tanzania, bus and train timetables use the 24-hour format. For example, if a bus from Dar es Salaam to Mwanza is scheduled to leave at 1630 hours, you know it leaves at 4:30 pm. This helps you plan when to reach the bus station so you are not late for your journey.