Time Conversion (Hours, Minutes, Seconds)
Time is measured in hours, minutes, and seconds. Converting between these units is needed to solve time problems — adding durations, comparing times, and finding totals.
In Class 4, you will learn the relationships between hours, minutes, and seconds, and how to convert between them.
What is Time Conversion (Hours, Minutes, Seconds) - Class 4 Maths (Time)?
The basic units of time are:
- 1 hour = 60 minutes
- 1 minute = 60 seconds
- 1 hour = 3,600 seconds (60 × 60)
Other useful conversions:
- 1 day = 24 hours
- 1 week = 7 days
Time Conversion (Hours, Minutes, Seconds) Formula
1 hour = 60 minutes | 1 minute = 60 seconds | 1 day = 24 hours
To convert to a smaller unit → multiply by 60.
To convert to a larger unit → divide by 60.
Solved Examples
Example 1: Example 1: Hours to minutes
Problem: Convert 3 hours to minutes.
Solution:
Step 1: 1 hour = 60 minutes
Step 2: 3 hours = 3 × 60 = 180 minutes
Answer: 3 hours = 180 minutes.
Example 2: Example 2: Minutes to hours and minutes
Problem: Convert 145 minutes to hours and minutes.
Solution:
Step 1: 145 ÷ 60 = 2 remainder 25.
Step 2: 145 minutes = 2 hours 25 minutes.
Answer: 2 hours 25 minutes.
Example 3: Example 3: Minutes to seconds
Problem: Convert 5 minutes to seconds.
Solution:
Step 1: 1 minute = 60 seconds
Step 2: 5 minutes = 5 × 60 = 300 seconds
Answer: 5 minutes = 300 seconds.
Example 4: Example 4: Seconds to minutes
Problem: Convert 200 seconds to minutes and seconds.
Solution:
Step 1: 200 ÷ 60 = 3 remainder 20.
Step 2: 200 seconds = 3 minutes 20 seconds.
Answer: 3 minutes 20 seconds.
Example 5: Example 5: Hours and minutes to minutes
Problem: Convert 2 hours 35 minutes to minutes only.
Solution:
Step 1: 2 hours = 120 minutes
Step 2: 120 + 35 = 155 minutes
Answer: 2 hours 35 minutes = 155 minutes.
Example 6: Example 6: Days to hours
Problem: How many hours are there in 3 days?
Solution:
Step 1: 1 day = 24 hours
Step 2: 3 days = 3 × 24 = 72 hours
Answer: 3 days = 72 hours.
Example 7: Example 7: Adding time durations
Problem: Aman studies for 1 hour 45 minutes in the morning and 2 hours 30 minutes in the evening. Find the total study time.
Solution:
Step 1: Add minutes: 45 + 30 = 75 minutes = 1 hour 15 minutes.
Step 2: Add hours: 1 + 2 + 1 = 4 hours.
Step 3: Total = 4 hours 15 minutes.
Answer: Total study time = 4 hours 15 minutes.
Example 8: Example 8: Comparing durations
Problem: Which is longer: 2 hours 50 minutes or 175 minutes?
Solution:
Step 1: Convert 2 hours 50 minutes to minutes: 2 × 60 + 50 = 170 minutes.
Step 2: Compare: 170 vs 175. 175 > 170.
Answer: 175 minutes is longer (by 5 minutes).
Example 9: Example 9: Movie duration
Problem: A movie is 135 minutes long. Express this in hours and minutes.
Solution:
Step 1: 135 ÷ 60 = 2 remainder 15.
Answer: The movie is 2 hours 15 minutes long.
Example 10: Example 10: Subtracting time
Problem: Priya's exam is 3 hours long. She has already used 1 hour 40 minutes. How much time remains?
Solution:
Step 1: Total = 3 hours = 2 hours 60 minutes (borrow 1 hour as 60 minutes).
Step 2: 2 hours 60 min − 1 hour 40 min = 1 hour 20 minutes.
Answer: 1 hour 20 minutes remain.
Key Points to Remember
- 1 hour = 60 minutes.
- 1 minute = 60 seconds.
- 1 day = 24 hours.
- To convert to smaller units → multiply.
- To convert to larger units → divide.
- When adding time, if minutes exceed 60, carry over to hours.
- When subtracting time, borrow 1 hour = 60 minutes if needed.
Practice Problems
- Convert 4 hours to minutes.
- Convert 210 minutes to hours and minutes.
- Convert 3 minutes 20 seconds to seconds.
- How many hours are in 2 days?
- Add: 1 hour 50 minutes + 2 hours 45 minutes.
- Which is longer: 3 hours 10 minutes or 200 minutes?
- A cricket match lasts 3 hours 30 minutes. Express in minutes.
Frequently Asked Questions
Q1. How many minutes are in 1 hour?
There are 60 minutes in 1 hour.
Q2. How many seconds are in 1 minute?
There are 60 seconds in 1 minute.
Q3. How do you convert hours to minutes?
Multiply the number of hours by 60. For example, 2 hours = 2 × 60 = 120 minutes.
Q4. How do you convert minutes to hours?
Divide by 60. The quotient is the hours and the remainder is the remaining minutes. 150 min = 150 ÷ 60 = 2 hours 30 minutes.
Q5. How many hours are in a day?
There are 24 hours in a day.
Q6. How do you add time durations?
Add minutes first. If the sum is 60 or more, convert to hours. Then add the hours. Example: 1 hr 50 min + 1 hr 20 min = 2 hr 70 min = 3 hr 10 min.
Q7. How do you subtract time?
If the minutes of the smaller time are larger, borrow 1 hour (= 60 min) from the hours. Example: 5 hr 20 min − 2 hr 45 min = 4 hr 80 min − 2 hr 45 min = 2 hr 35 min.
Q8. How many seconds are in 1 hour?
1 hour = 60 minutes × 60 seconds = 3,600 seconds.
