How to use this calculator

Pick which three quantities you know, then enter them. Use signs consistently: choose a positive direction and make velocities and accelerations against it negative.

Formulas

Velocityv = v₀ + at

Displacements = v₀t + ½at² = ½(v₀ + v)t

Without timev² = v₀² + 2as

Worked example

Car at 5 m/s accelerating at 2 m/s² for 6 s (the default)

v = 5 + 2 × 6 = 17 m/s.
s = 5 × 6 + ½ × 2 × 6² = 66 m.
Check: 17² = 289 and 5² + 2 × 2 × 66 = 289. ✓

Frequently asked questions

Can I use this for free fall?

Yes. Use a = −9.81 m/s² with up as positive (or +9.81 with down as positive).

What if acceleration changes?

These equations do not apply. Integrate a(t) to get velocity and position, or split the motion into stretches of constant acceleration.