Speed Calculator
Speed = Distance / Time
Fill in any two values to calculate the third
Free Online Speed, Distance & Time Calculator
Use this calculator to solve any of the three variables in the fundamental speed equation: Speed = Distance / Time. Simply enter any two known values and the third is calculated instantly. Supports multiple unit systems including metric and imperial, so you can work in km/h, mph, m/s, and more without manual conversions.
How to Use
Enter values into any two of the three fields (Speed, Distance, Time). The calculator automatically detects which field is empty and computes it using the speed formula. Select your preferred units from the dropdowns beneath each field. All unit conversions happen behind the scenes. To change which value is calculated, clear one field and fill in the other two. Click Reset to start over.
FAQ
What is the formula for speed?
Speed equals distance divided by time (S = D / T). To find distance, multiply speed by time (D = S x T). To find time, divide distance by speed (T = D / S). These three rearrangements cover every scenario.
How do I convert between km/h and mph?
To convert km/h to mph, divide by 1.60934. To convert mph to km/h, multiply by 1.60934. This calculator handles all conversions automatically when you select different units.
Can I mix different unit systems?
Yes. You can enter speed in mph, distance in kilometers, and time in minutes. The calculator converts everything to base metric units (m/s, meters, seconds) internally before computing, then converts the result back to your chosen output unit.
What is the difference between speed and velocity?
Speed is a scalar quantity that refers to how fast an object is moving regardless of direction. Velocity is a vector quantity that includes both the speed and the direction of movement. This calculator works with speed (magnitude only).