Elapsed Time

Elapsed time is the amount of time that passes from start to finish. If a movie starts at 2:00 and ends at 4:00, the elapsed time is 2 hours. Figuring out elapsed time is a useful math skill.

How to Find Elapsed Time

To find elapsed time, subtract the start time from the end time. If you start homework at 3:30 and finish at 4:15, you count forward. From 3:30 to 4:00 is 30 minutes. From 4:00 to 4:15 is 15 minutes. The total is 45 minutes.

A number line can help. Draw a line, mark the start and end times, and count the jumps between them.

Using Elapsed Time

You use elapsed time every day. How long until recess? How long does the bus ride take? How many minutes until dinner?

Elapsed time helps you plan your day. If you know soccer practice lasts 90 minutes and starts at 5:00, you know it ends at 6:30.

Fun Facts

• A school day is usually about 6 to 7 hours of elapsed time.
• The fastest marathon runners finish in a little over 2 hours.
• One day has 1,440 minutes of elapsed time from midnight to midnight.

Did You Know?

Astronauts on the International Space Station see a sunrise every 90 minutes because they orbit Earth so fast!