What is duration?
Duration is how long something lasts, from a start time to an end time. It answers questions like 'How long was the film?' or 'How long did the journey take?'. To find it, we subtract: duration = end time − start time.
Worked example
A cartoon starts at 3:15 p.m. and ends at 3:50 p.m. How long is it?
From 3:15 to 3:50 is 50 − 15 = 35 minutes.
Changing between hours and minutes
Remember that 1 hour = 60 minutes. So 1 hour 30 minutes = 60 + 30 = 90 minutes. To go the other way, 90 minutes = 1 hour 30 minutes. Counting on a clock face is a helpful way to check a short duration.
Key idea
Half an hour = 30 minutes.
1 hour = 60 minutes.
Count on the clock to check your duration.
Remember
- Duration is a length of time, not a clock time.
- End − start gives the duration.
- Use 60 minutes = 1 hour when changing units.