Displacement Calculator
Find displacement from velocity, acceleration and time using the SUVAT equations, plus final velocity, distance travelled and a position-time table.
Displacement is the straight-line change in position from start to finish, with a direction, measured in metres. For anything moving with constant acceleration it follows from the equations of motion (often called SUVAT). Enter three of the quantities you know and this calculator gives the displacement, the missing velocity, acceleration or time, and how far the object actually travelled along its path.
How to use this tool
- Choose which three quantities you know.
- Enter velocities in m/s and acceleration in m/s². A negative acceleration points along the negative axis; it slows motion only while velocity is positive.
- Enter the time in seconds, unless your method uses final velocity and acceleration instead.
- Read the displacement and check the table to see position and velocity at ten equal steps.
Formula
s = u·t + ½·a·t² s = (u + v)·t / 2 s = (v² − u²) / (2a)
s is displacement, u the initial velocity, v the final velocity, a the constant acceleration and t the time. If the velocity reverses during the interval, the path length is found by adding the distance before the turning point (t = −u/a) to the distance after it.
Example
A cyclist rolling at 5 m/s accelerates at 2 m/s² for 10 s. s = 5 × 10 + ½ × 2 × 10² = 50 + 100 = 150 m. The final velocity is 5 + 2 × 10 = 25 m/s and the average velocity is 150 ÷ 10 = 15 m/s.
Frequently asked questions
What is the difference between displacement and distance?
Distance is the total length of the path; displacement only compares the start and end points. A ball thrown up at 10 m/s that falls back to your hand has travelled about 10 m but has zero displacement.
Can displacement be negative?
Yes. A negative displacement means the object finished on the opposite side of its starting point from the direction you called positive.
Do these formulas work when acceleration changes?
No. They assume constant acceleration. For changing acceleration you need the area under the velocity–time graph, for example by splitting the motion into short steps with roughly constant acceleration.
How do I use km/h?
Divide km/h by 3.6 to get m/s before entering it (90 km/h = 25 m/s).
Sources
Last updated: 2026-10-30