Speed Calculator
The Speed Calculator computes speed from distance and time. It is useful for travel planning, running, driving, and physics problems where you need to know how fast something is moving.
Speed Calculator
km
hours
What the result means
Speed is the distance covered per unit of time. A higher speed means more distance covered in the same time. The result is shown in both km/h (common for driving) and m/s (common in physics).
How to use this calculator
- 1Enter the distance traveled in kilometers (km).
- 2Enter the time taken in hours.
- 3Press Calculate to see the speed in km/h and m/s.
- 4Review the formula speed = distance ÷ time.
- 5Adjust the inputs to compare different journeys.
The formula
The calculation uses a standard, verifiable formula. Here it is in its simplest form.
Speed (v) = Distance (d) ÷ Time (t)
v = d / t
To convert km/h to m/s: divide by 3.6
What each variable means
| Symbol | Name | Description |
|---|---|---|
| d | Distance | The distance traveled, measured in kilometers. |
| t | Time | The time taken, measured in hours. |
| v | Speed | The rate of travel, measured in km/h or m/s. |
Step-by-step example
Example: 100 km in 2 hours
Distance:100 kmTime:2 hours
- 1Speed = 100 ÷ 2
- 2= 50 km/h
- 3In m/s: 50 ÷ 3.6 = 13.89 m/s
Result
50 km/h (13.89 m/s)
What changes the result
- Speed depends on both distance and time.
- Average speed differs from instantaneous speed during a journey.
- Traffic, stops, and acceleration affect real-world average speed.
Edge cases to be aware of
Unusual situations handled correctly
- If time is zero, speed is undefined — the calculator returns 0.
- Very short times with long distances produce very high speeds.
- The calculator assumes constant speed over the journey.
Common mistakes
Avoid these errors
- Using minutes instead of hours without converting.
- Confusing average speed with instantaneous speed.
- Forgetting to convert units when comparing speeds.
Assumptions
- The speed is constant over the entire journey.
- Distance and time are measured accurately.
- Standard metric units are used.
Limitations
- Assumes constant speed; real journeys have varying speeds.
- Does not account for stops, acceleration, or deceleration.
- Requires accurate distance and time measurements.
Frequently asked questions
What is the difference between speed and velocity?+
Speed is a scalar — it only tells you how fast something moves. Velocity is a vector — it includes both speed and direction. This calculator computes speed.
How do I convert km/h to m/s?+
Divide the speed in km/h by 3.6. For example, 72 km/h ÷ 3.6 = 20 m/s.
What is average speed?+
Average speed is the total distance divided by the total time. It does not reflect variations in speed during the journey.