Speed from Distance and Time Calculator
Calculate average speed from a distance and a time, in mph, km/h, and m/s, with flexible units. Runs in your browser.
Average speed = distance ÷ time. This gives the average over the whole trip, not instantaneous speed. Units are converted via exact factors (1 mile = 1609.344 m, 1 m/s = 2.23694 mph). Everything runs in your browser.
About this tool
Speed is one of the three quantities in the fundamental relationship of motion — speed, distance, and time — and this calculator solves for speed given the other two. The formula is simply speed = distance ÷ time, and the tool handles the unit conversions so you can mix and match: enter a distance in miles, kilometers, meters, or feet and a time in hours, minutes, or seconds, and it returns the average speed in miles per hour, kilometers per hour, and meters per second simultaneously. For example, covering 60 miles in 1.5 hours is an average of 40 mph (about 64 km/h). The key word is average: this gives the constant speed that would cover the same distance in the same time, not the instantaneous speed at any moment — a car that speeds up and slows down still has a well-defined average over the trip. The conversions use exact factors (one mile is 1609.344 metres, and one metre per second equals 2.23694 mph), so the results are precise. This is the everyday calculation behind working out travel speed, race pace, the velocity of a moving object in physics homework, or how fast you'd need to go to cover a distance in a given time. It pairs with the two companion tools that solve the same relationship for the other variables — distance from speed and time, and time from distance and speed. Everything runs in your browser; nothing is uploaded.
How to use it
- Enter the distance traveled and choose its unit.
- Enter the time taken and choose its unit.
- Read the average speed in mph, km/h, and m/s.
- Mix units freely — e.g. meters and seconds, or miles and minutes.
Frequently asked questions
- How do you calculate speed from distance and time?
- Speed = distance ÷ time. For example, 60 miles in 1.5 hours is 40 mph. The tool converts units automatically and shows mph, km/h, and m/s at once.
- Is this average or instantaneous speed?
- Average speed — the constant speed that would cover the same distance in the same time. It does not capture moment-to-moment changes in speed during the trip.
- Can I mix units like meters and minutes?
- Yes. Pick any distance unit (miles, km, meters, feet) and any time unit (hours, minutes, seconds); the calculator converts and gives consistent results in all three speed units.
- How do I convert m/s to mph?
- Multiply m/s by 2.23694 to get mph, or by 3.6 to get km/h. The tool does this conversion for you from the computed speed.
- What if my time is zero?
- Speed is undefined for zero time (division by zero), so enter a positive time. Any nonzero time gives a finite average speed.
- Is anything uploaded?
- No. The calculation runs entirely in your browser.