Solve motion problems in seconds. Enter any three of displacement s, initial velocity u, final velocity v, acceleration a and time t, and this free SUVAT kinematics calculator picks the right equations and shows the working. Switch to projectile motion for range, maximum height and time of flight with a trajectory graph.
Fill exactly three boxes, in SI units (m, m/s, m/s², s). Use negative numbers for opposite directions, e.g. a = −9.81 for upward throws.
The five SUVAT equations
Each equation leaves out one of the five quantities. With three known values, the calculator chooses the equation that skips the unknown you don’t need, solves it, then fills in the rest. They only apply when acceleration is constant, such as free fall (a = 9.81 m/s² near Earth’s surface) or a car braking steadily.
Projectile motion formulas
Worked example
A stone is dropped from rest (u = 0) and falls for 3 s with a = 9.81 m/s². Then v = 0 + 9.81 × 3 = 29.4 m/s and s = ½ × 9.81 × 3² = 44.1 m. A ball kicked at 20 m/s and 45° from the ground lands 40.8 m away after 2.88 s, peaking at 10.2 m. Air resistance is ignored.
Frequently asked questions
What does SUVAT stand for?
s = displacement, u = initial velocity, v = final velocity, a = acceleration and t = time. The SUVAT equations link these for motion in a straight line with constant acceleration.
How do I use the kinematics calculator?
Type any three known values in SI units and leave the other two blank, then press Solve. The calculator shows both unknowns and the equations it used.
Why are there two answers sometimes?
When you know s, a and u (or v) but not t, the maths involves a square root, so two times can fit, for example a ball passing the same height on the way up and down. Both valid answers are shown.
What angle gives the maximum range?
On level ground and without air resistance, 45° gives the longest range. Launching from a height, the best angle is a little less than 45°.
Does it include air resistance?
No. Like textbook kinematics, it assumes constant acceleration and no drag, which is accurate for dense, slow objects over short distances.
Related tools
Free educational tool by HawkInc. Results are calculated in your browser and rounded for display; check critical work by hand or with a second method.