What are Various Units of Time Measurement? - BYJUS

Measurement of Time Using Units

Keeping track of time helps us remember the events that occurred in the past, record the events happening in the present and plan for the events scheduled for the future. Time is a linear quantity that doesn’t travel backwards. Time can be measured in different units. We choose the unit that is suitable for the span of time that we want to measure....Read MoreRead Less

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What is Time?



Time can be considered as a series of events that occur one after another. Tracking time helps us keep a record of the events that have already happened in the past, the events that are happening right now, and events that will happen in the future. We can use time to measure the duration of events happening around us.

Why do we keep Track of Time?


We keep track of time to simplify our day-to-day activities. By keeping track of time, we are able to follow a daily routine. We know when the Sun rises and when it sets. This helps us do most of our productive work during daytime and get some rest when it is dark. Keeping track of time also allows us to record events, and predict and plan the events in our future.

Units of Time



Some of the basic units of time are second, minute, hour, day, week, month, and year. We estimate time using different units depending on the span of time we are trying to measure. For example, we measure the time we take to climb one flight of stairs in seconds. The time we take to brush our teeth in the morning can be measured in minutes. The time we spend sleeping in a day can be measured in hours. So, the unit that we choose to measure time depends on the span of time that we want to measure.

Relation between units of Time

The units of time are related to each other, and time measured in one unit can be converted into another unit by following a few simple calculations. The relationship between each unit of time is as follows:


Conversion of Units for Time:

1 Minute

60 seconds

1 hour

60 minutes (or) 3600 seconds

1 day

24 hours

1 week

7 days

1 year

365 days

How do we tell Time?


We use clocks and watches to measure time. There are two types of clocks: analog and digital. An analog clock has numbers from 1 to 12 that tells us the hour, and it has 60 dashes that are used to express the minutes.


We tell time by observing the positions of the hour hand and the minute hand at a particular instant. The hour hand is shorter than the minute hand, in most clocks. If the hour hand is at 8 and the minute hand is at 12, this means the time is 8 o’clock. Similarly, if the hour hand is at 9 and the minute hand is at 6, the time is 9:30. 


A digital clock does not have a minute hand or an hour hand. This clock displays the time for us and tells us the time in hours and minutes directly. Either of these two types of clocks can be used to tell time.

What is AM and PM?




As you know, we have 24 hours in a day. But there are only 12 hours on the clock. That means a clock will show a particular time exactly twice in a single day. For example, an analog clock will show you 10 o’clock two times in a day; once in the morning, and once at night. So, we must be able to distinguish between the two instances where the clock shows 10 o’clock and determine whether it is daytime or nighttime.




We can divide the 24 hours in a day into 2 equal parts. The first 12 hours is identified as AM or ante meridiem, which means “before midday”. The remaining 12 hours is identified as PM or post meridiem, which means “after midday”.


A new day starts at 12 midnight or 12am, runs through 12 noon or 12pm, and ends just before midnight. Sunrise happens between 12am and 12pm, and sunset takes place between 12pm and 12am.

How to tell Time using AM and PM

We need to be aware of our surroundings to tell time using AM and PM by looking at an analog clock. If the clock shows 1 o’clock and the Sun is directly above us moving to the west, that means the time is 1pm. When your Mom says you must have your breakfast by 8 o’clock, that means you need to have your breakfast by 8 am, as breakfast is the meal we have in the morning. On the other hand, we usually have dinner after 6 o’clock or 6 pm in the evening. Normally, school starts in the morning or AM and ends in the afternoon or PM.


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Solved Units of Measurement of Time Examples

Example 1: It’s sunny outside. Write the time on the clock.





The hour hand points between the 3 and the 4 on the clock. So, it’s past 3 o’clock, but it is not 4 o’clock yet. 


The minute hand points at the 5. The minute hand takes 5 minutes to move from one number to the next number, that is, it takes 5 minutes to cover an interval between 2 numbers. Between 12 and 5 there are 5 intervals. Hence the time required for it to move from 12 to 5 is 5 + 5 + 5 + 5 + 5 = 25 minutes. 


So, the time is 3:25, or 25 minutes past 3. 


Since it is sunny outside, the time is expressed as 3:25 pm.


Example 2: Phil woke up at this time. Write the time.




Write the time using AM and PM.



The hour hand of the clock is between the 8 and the 9. So, it’s past 8 o’clock, but it is not 9 o’clock yet. The minute hand takes 5 minutes to move from one number to the next number, that is, it takes 5 minutes to cover an interval between 2 numbers. Between 12 and 3 there are 3 intervals. Since the minute hand is at 3, it’s been 5 + 5 + 5 = 15 minutes since it has been 8 o’clock. 


We usually leave for school in the morning. Hence, the actual time is 8:15 am. 


Example 3: This is what Tiffany’s daily routine looks like:

6:00__: Wake up

7:30__: Breakfast

9:00__: Arrive at the office

11:00__: Tea break

1:30__: Lunch break

6:00__: Arrive at home

10:00__: Go to bed

Write AM or PM in the blanks. 



Since people wake up and start their daily routine in the morning, the time will be AM. The time changes to PM at 12 noon. It changes back to AM at 12 midnight. So, Tiffany’s routine is:


6:00 am: Wake up

7:30 am: Breakfast

9:00 am: Arrive at the office

11:00 am: Tea break

1:30 pm: Lunch break

6:00 pm: Arrive at home

10:00 pm: Go to bed


Example 4: Use the times to complete the timeline. Write an activity that you might be involved in during those times.





AM is before 12 noon and PM is at 12 noon and after. So, the blank before 9:30 am should be 7:30 am. 


The missing time between 9:30am and 3:30pm is 1:00pm. 9:30pm comes after 7:00pm. 


You might wake up at 7:30 am, have your lunch at 1:00 pm, and go to bed at 9:30 pm. 



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Frequently Asked Questions on Units of Time

Hours, minutes, and seconds are units of time. An hour is bigger than a minute, and a minute is bigger than a second. An hour consists of 60 minutes and 1 minute consists of 60 seconds.

If the digital clock displays am and pm, then they are represented as 12 : 00 am and 12 : 00 pm but if am and pm is not displayed then 12 am is represented as 0 : 00, as it shows the start of the new day and 12 pm is represented as 12 : 00.

The minute hand takes 1 hour or 60 minutes to complete a whole round, that is, when it moves from 12 and reaches back to 12. Quarter means \(\frac{1}{4}\)th or one-fourth of something. One fourth of 60 minutes is 15 minutes. So “quarter to” means 15 minutes before and “quarter past” means 15 minutes after. Similarly half represents 30 minutes so “half past” means 30 minutes after.