About this calculator
Use it for a road trip, a train journey or a Class 9 motion problem.
How to use it
- Choose what to find, enter the other values with their units, and read the answer in every common unit.
The formula
speed = distance ÷ time; distance = speed × time; time = distance ÷ speed
- v
- speed
- d
- distance
- t
- time
Worked example
150 km in 2 hours 30 minutes
- Time = 2.5 h.
- Speed = 150 ÷ 2.5 = 60 km/h, or 16.67 m/s.
What the result means
This is the average speed over the whole journey, including slow stretches and stops if the time includes them.
Assumptions
- Average speed over the trip.
Limitations
- It does not model acceleration; use the acceleration calculator for that.
Frequently asked questions
How do I convert km/h to m/s?
Divide by 3.6. 72 km/h is 20 m/s.
How long does 300 km take at 80 km/h?
3.75 hours, or 3 hours 45 minutes.
What is average speed?
Total distance divided by total time.
Last reviewed on 6 October 2026. Found a mistake? Tell us.