Speed = distance / time. Distance = speed x time. Time = distance / speed.
What is a Speed, Distance & Time Calculator?
A speed, distance and time calculator works out any one of the three quantities when you know the other two, using the relationship distance = speed x time. Pick the value you want to find, enter the two you know, and read the answer instantly. Each input has its own unit, so you can combine kilometers with hours, miles with minutes, or meters with seconds without any manual conversion. It is useful for planning a road trip, checking a runner's or cyclist's average speed, working out flight or sailing times, or solving physics homework. Behind the scenes everything is converted to SI base units, computed, and then shown in the unit you choose.
How to Use
1. Choose what you want to find: Distance, Speed, or Time.
2. Enter the two known values and select a unit for each.
3. Read the result, and change the output unit to see it in km, m/s, mph, hours, and more.
4. The auxiliary boxes show the same answer in several common units at once.
Formula & Definition
The three forms of one equation are:
Distance = Speed x Time (d = v x t)
Speed = Distance / Time (v = d / t)
Time = Distance / Speed (t = d / v)
For example, traveling at 60 km/h for 2 hours covers 60 x 2 = 120 km. Covering 100 km in 2 hours gives 100 / 2 = 50 km/h. Covering 150 km at 50 km/h takes 150 / 50 = 3 hours. Internally values are converted to meters, meters per second, and seconds, so any mix of units gives the correct answer.
Interpreting Results
Average speed is total distance divided by total time, so it smooths over stops and changes in pace; a 50 km/h average can hide both 80 km/h stretches and time spent at rest. When solving for time, the result assumes a constant speed, which is an idealization for real journeys with traffic, terrain, and breaks. Use the output unit selector to compare the same figure in metric and imperial units, and remember that small differences in unit choice (m/s vs km/h) represent the same physical quantity.
Frequently Asked Questions
How do I calculate speed from distance and time? ▾
Divide distance by time: speed = distance / time. For example 100 km in 2 hours is 50 km/h. The tool also shows the result in m/s, mph, and knots.
Can I mix units, like miles and minutes? ▾
Yes. Each field has its own unit selector. Values are converted to SI base units before computing, and the answer can be shown in any unit you pick.
How do I find travel time? ▾
Select 'Find Time', enter the distance and the speed, and the tool returns time = distance / speed. For example 150 km at 50 km/h takes 3 hours.
What is the difference between speed and velocity? ▾
Speed is how fast you move (a magnitude); velocity also includes direction. This calculator deals with speed and the scalar distance traveled.