Enter any two of speed, distance, and time — the Speed Calculator solves for the missing third value. Choose what you want to solve for, pick your preferred units for each measurement, and get your answer right away. Supports common units like mph, km/h, m/s, miles, kilometers, hours, minutes, and seconds.
Result
--
Solving For
--
Speed in m/s
--
Speed in km/h
--
Speed in mph
--
Distance in km
--
Time (hh:mm:ss)
--
Speed is the measure of how fast an object moves over a given distance in a period of time. In physics, it is defined as the rate of change of position. The SI unit for speed is meters per second (m/s), though km/h, mph, and knots are also widely used depending on context.
The basic formula is: Speed = Distance ÷ Time. From this you can derive Distance = Speed × Time, and Time = Distance ÷ Speed. This calculator lets you solve for any of the three variables as long as you know the other two.
Average speed is the total distance traveled divided by the total time taken: average speed = total distance / total time. It does not account for direction, only the magnitude of movement. For example, if you travel 100 km in 2 hours, your average speed is 50 km/h.
No. Speed is a scalar quantity — it only describes how fast an object is moving. Velocity is a vector quantity that includes both speed and direction. For example, 60 km/h is a speed, while 60 km/h heading north is a velocity.
The most common units of speed are meters per second (m/s), kilometers per hour (km/h), miles per hour (mph), feet per second (ft/s), and knots (kn). Knots are used in aviation and maritime navigation. This calculator supports conversions between all these units.
To convert miles per hour to meters per second, multiply by 0.44704. For example, 60 mph × 0.44704 = 26.82 m/s. This calculator automatically displays your result converted into multiple speed units simultaneously.
Most studies suggest that fuel efficiency peaks between 45–65 mph (72–105 km/h) for typical passenger vehicles. Driving faster increases aerodynamic drag significantly, reducing fuel economy. The optimal speed varies by vehicle type and road conditions.
To find time, rearrange the speed formula: Time = Distance ÷ Speed. For instance, if you drive 150 km at 60 km/h, the time taken is 150 ÷ 60 = 2.5 hours, or 2 hours and 30 minutes. Select 'Solve for Time' in this calculator and enter your known distance and speed values.