Calculate the acceleration of an object based on start and end velocity and the time it takes to change speed.
Acceleration (a) tells you how much the speed changes per unit of time, and is measured in meters per second squared (m/s²). It's calculated by taking the final velocity (v₂) minus the initial velocity (v₁), divided by the time (t) the change took.
If the acceleration is negative, it means the object is slowing down — this is often called deceleration or negative acceleration, but it's still acceleration in the physical sense.
Negative acceleration means the speed is decreasing over time, i.e. the object is slowing down. In everyday language this is often called deceleration, but mathematically it's just acceleration with a negative sign.
Acceleration is measured in meters per second squared, written m/s². This tells you how many meters per second the speed changes for each second that passes.
According to Newton's second law, the force acting on an object equals mass times acceleration (F = m × a). The greater the force acting on a given mass, the greater the acceleration. See the force calculator to calculate this directly.