Motion · Mechanics

Kinematics Calculator for Constant Acceleration

Solve displacement, velocity, acceleration, or time from a compatible set of constant-acceleration measurements.

Formula shown Runs locally Reviewed Aug 11, 2026

Equation guide

One-dimensional motion with constant acceleration

Velocity law

v = u + at

Position law

s = ut + at²/2

Time-independent relation

v² = u² + 2as

Motion solver

Constant-acceleration kinematics

Solve for

Initial velocity u (m/s)

Manual entry: up to 3 decimal places; scientific notation is accepted with the same mantissa rule · button step: 0.5 m/sFinal velocity v (m/s)

Manual entry: up to 3 decimal places; scientific notation is accepted with the same mantissa rule · button step: 0.5 m/sAcceleration a (m/s²)

Manual entry: up to 3 decimal places; scientific notation is accepted with the same mantissa rule · button step: 0.5 m/s²Time t (s)

Manual entry: up to 3 decimal places; scientific notation is accepted with the same mantissa rule · button step: 0.5 s

How updates work: enter a compatible set of known values. When displacement is selected and you impose a final velocity, the calculator treats the initial velocity and time as fixed, then derives the required acceleration from a = (v − u) / t before updating the displacement.

Signed quantities use the selected positive direction; displayed values use up to three decimals.

SUVAT

Enter a compatible set of three known values.

Using the model

Symbols, assumptions and limitations

Interpretation notes

Motion is one-dimensional and acceleration is assumed constant. Signs indicate direction. When v² = u² + 2as is the only compatible equation for an unknown velocity, it determines magnitude but not direction; the calculator reports the principal non-negative root and explains that limitation.

Worked examples

See the method in practice

Starting from rest

With u = 0, a = 2 m/s², and t = 5 s, displacement is 25 m and final velocity is 10 m/s.

Braking

Negative acceleration represents motion slowing in the chosen positive direction.

Questions

Frequently asked

Why are three known values required?

A compatible SUVAT equation needs three known quantities to isolate one unknown.

Can acceleration be negative?

Yes. Negative acceleration indicates direction, not automatically slowing down.

Why can a velocity result be only the positive root?

An equation containing only squared velocities determines speed magnitude, not direction. Without time or another directional condition, both signs may be mathematically possible, so the calculator displays the principal non-negative root and flags the ambiguity.

Sources & review

Equations and examples are checked against the references below. Results are educational and should be independently verified for safety-critical work.

OpenStax Physics — motion equations

Written by the STEM Hub editorial team · Reviewed August 11, 2026 · Review methodology