Acceleration Calculator
Find acceleration from a change in velocity, from displacement and time, or from force and mass (F = ma). Results in m/s², g and ft/s².
Acceleration is how quickly velocity changes, measured in metres per second every second (m/s²). This calculator gets it three ways: from signed start and end velocities over a time, from displacement in a time, or from the net force on a known mass using Newton's second law. Results are also given in g, which makes car, ride and aircraft figures easier to compare.
How to use this tool
- Choose what you know: two velocities and a time, a displacement and a time, or a force and a mass.
- Pick the velocity unit (m/s, km/h, mph or ft/s). Displacement is in metres, force in newtons, mass in kilograms.
- Enter the values for your method; the other fields are ignored.
- Read the acceleration in m/s², g and ft/s². A negative value points along the negative coordinate direction.
Formula
a = (v − u) / t a = 2(d − u·t) / t² a = F / m
u is the initial velocity, v the final velocity, t the time, d the signed displacement, F the net force and m the mass. The displacement formula assumes constant acceleration. The velocity method gives an interval average; its extra displacement estimate also assumes constant acceleration.
Example
A car goes from 0 to 100 km/h in 8 seconds. 100 km/h is 27.78 m/s, so a = 27.78 ÷ 8 = 3.472 m/s², or about 0.354 g. If the push was steady, it covered (0 + 27.78) ÷ 2 × 8 ≈ 111.1 m while doing it.
Frequently asked questions
What does an acceleration of 1 g mean?
It is the conventional standard acceleration 9.80665 m/s², close to free fall near Earth but not the exact local gravity everywhere. A car pulling 0.5 g gains about 4.9 m/s (17.7 km/h) of speed every second.
Can acceleration be negative?
Yes. Acceleration has a direction. If it points against the motion, the object slows down; people often call this deceleration. Braking from 60 mph to a stop in 4 seconds is about −6.7 m/s².
Is this the same as average acceleration?
The velocity method gives the average acceleration over the interval. If the acceleration changed during that time, the peak could be higher; the average acceleration calculator can also split a list of readings into segments.
Why use net force for F = ma?
Only the unbalanced force changes motion. If an engine pushes with 4,000 N while drag and rolling resistance oppose it with 1,000 N, the net force is 3,000 N.
Sources
Last updated: 2026-10-30