What is duration?
Duration is how long an event lasts. To find it, we work out the time from the start to the end.
Key idea
Duration = end time − start time. Remember 1 hour = 60 minutes, so we count hours and minutes separately.
Counting the time
Start at the beginning time and count forward to the end time. Count full hours first, then the extra minutes.
Worked example
A cartoon starts at 2:00 p.m. and ends at 4:30 p.m. From 2:00 to 4:00 is 2 hours. From 4:00 to 4:30 is 30 minutes. So the duration is 2 hours 30 minutes.
Sometimes an event ends in the next hour. A football game runs from 4:50 p.m. to 5:20 p.m. From 4:50 to 5:00 is 10 minutes, then 5:00 to 5:20 is another 20 minutes. Adding them, 10 + 20 = 30 minutes. Counting to the next full hour first keeps this simple and stops us making mistakes.
Remember
- 60 minutes make 1 hour.
- Count the whole hours first, then the minutes.
- When crossing an hour, count up to the o'clock, then on.
- Check: start time + duration should give the end time.