Acceleration Calculator
Find acceleration from a change in velocity over time — a = (v − u) ÷ t.
Reviewed by the OmniCalc teamMethod verified 2026-07-01
5m/s²
= 0.509858 g= 18 km/h/s
Acceleration 5 m/s²Show steps
- Change in velocity: Δv = v − u = 20 m/s − 0 m/s = 20 m/s.
- a = Δv ÷ t = 20 m/s ÷ 4 s = 5 m/s².
- Convert to g-force: 5 m/s² ÷ 9.80665 = 0.509858 g.
How to use the acceleration calculator
- 1Enter the initial velocity u and final velocity v in m/s.
- 2Enter the time t in seconds over which the change happened.
- 3Read the acceleration, with the working shown under Show steps.
What the sign means
A positive acceleration means the object is speeding up; a negative one means it is slowing down. For scale, free fall at Earth’s surface is about 9.81 m/s², which is 1 g.
Frequently asked questions
What is the acceleration formula?
Acceleration is the change in velocity divided by the time it took: a = (v − u) ÷ t, where u is the initial velocity and v is the final velocity.
What units does this use?
Metres per second (m/s) for the velocities and seconds (s) for time, giving acceleration in m/s². The result is also shown in g-force, where 1 g equals 9.80665 m/s².
Can acceleration be negative?
Yes. A negative value means the object is slowing down — the final velocity is lower than the initial velocity. This is often called deceleration.