Calculating Time Intervals: Step-by-Step Example
23 October 2026
Understanding how to work out time intervals is a key part of reading and calculating time. Many children find it easier when they break the problem into smaller steps, moving from one time to the next.
Worked example
Question: What is the time interval between 2:15 pm and 4:40 pm?
Step 1: Start at 2:15 pm.
Step 2: Count up to the next full hour. 2:15 pm to 3:00 pm is 45 minutes.
Step 3: Count the full hours. 3:00 pm to 4:00 pm is 1 hour.
Step 4: Count the minutes from 4:00 pm to 4:40 pm. That is 40 minutes.
Step 5: Add all the time intervals. 45 minutes + 1 hour + 40 minutes.
Step 6: Add the minutes together. 45 + 40 = 85 minutes. 85 minutes is 1 hour and 25 minutes.
Step 7: Add the hours. 1 hour + 1 hour = 2 hours. Don't forget the extra 25 minutes.
The correct answer is 2 hours and 25 minutes.
After this example, your child will know how to spot the start and end times, count minutes and hours in between, and add them together. Key insight: Practising this type of question helps children feel confident with time interval problems in 11+ maths.
