Acceleration Calculator
Fill in any three of acceleration, final velocity, initial velocity, and time, and it works out the fourth.
Fill in any three fields and leave the fourth blank — the calculator solves for the one you left empty using a = (v_final − v_initial) / t.
Acceleration
5m/s²
Time
6s
Final velocity
30m/s
Initial velocity
0m/s
How it works
Acceleration measures how quickly velocity changes. Subtract the starting velocity from the ending velocity, divide by the time it took, and you have it. Go from a standstill to 30 m/s in 6 seconds and you accelerated at 5 m/s² on average.
The same relationship rearranges four ways. Know the acceleration and how long it lasted? You can predict the final speed. Know where you ended up and how hard you were accelerating? You can back out how long it took. Leave one box empty and the calculator picks the matching form for you.
A negative result just means you slowed down — deceleration is acceleration pointing the other way. And because this is average acceleration, it smooths over any bumps in between; a real journey with hard braking and hard throttle can still average out to the same figure.
Frequently asked questions
What units does this use?
Velocities in meters per second and time in seconds give acceleration in m/s², the SI unit. If your speeds are in km/h, convert them to m/s first (divide by 3.6) so everything lines up.
Why is my acceleration negative?
A negative value means the object is slowing down over that interval — the final velocity is smaller than the initial one. Physicists call that deceleration, but mathematically it's just acceleration in the opposite direction.
Can I find the final velocity instead?
Yes. Leave the final velocity box blank and fill in acceleration, initial velocity, and time. The calculator uses v_f = v_i + a·t to fill it in.