MotionLab

Acceleration Calculator

a = (v₁ − v₀) / t, in metres per second squared.

Initial velocity (m/s)

Final velocity (m/s)

Time (s)

Acceleration (m/s²)

a = (v₁ − v₀) / t

What you entered

Initial velocity (m/s): 0Final velocity (m/s): 27Time (s): 3

1
Change in velocity
27 − 0= 27
2
Divide by time
27 ÷ 3= 9

Result

Acceleration (m/s²): 9

Going from 0 m/s to 27 m/s over 3s gives an acceleration of 9 m/s².

Acceleration from a change in velocity

Acceleration is the change in velocity divided by the time taken. Negative values mean slowing down.

Start velocity (m/s)	End velocity (m/s)	Time (s)	Acceleration (m/s2)
0	27.8	10	2.780
0	100	5	20.000
20	0	4	-5.000
0	60	8	7.500
10	30	5	4.000
0	9.81	1	9.810

The first row is roughly a family car reaching 100 km/h in 10 seconds, at 2.78 m/s2 or about 0.28 g. The last row is free fall at the surface of the Earth by definition. Row three is deceleration, which is just negative acceleration - the sign tells you the direction of the change, not whether something is speeding up in absolute terms. This formula assumes the acceleration is constant across the interval; real vehicles accelerate hardest in the low gears, so a measured 0-100 time gives the average rather than the peak.

The rate velocity changes

Acceleration measures how quickly speed changes over time — a car that goes from 0 to 27 m/s in 3 seconds has an acceleration of 9 m/s² for every second it speeds up by 9 m/s.

Positive and negative acceleration

A negative result means the object is slowing down (decelerating) rather than speeding up — the same formula covers braking as easily as it covers a launch.

Frequently asked questions

A car goes from 0 to 60 mph (26.8 m/s) in 7 seconds. What's the acceleration?

a = Δv/Δt = 26.8/7 = 3.83 m/s². That's about 0.39 g (times gravitational acceleration). A sports car doing 0–60 in 3.5 seconds hits 7.66 m/s² — nearly twice as much.

How is acceleration different from velocity?

Velocity tells you how fast something is moving (m/s). Acceleration tells you how fast the velocity is changing (m/s²). You can be moving at high speed with zero acceleration (cruise control), or accelerating from a standstill. See the velocity calculator for speed problems.

What does negative acceleration mean?

Deceleration — the object is slowing down. A car braking from 30 m/s to 0 in 5 seconds has a = (0−30)/5 = −6 m/s². The negative sign indicates the velocity is decreasing, not that there's less force — braking can require just as much force as accelerating.

What is gravitational acceleration?

On Earth, objects in free fall accelerate at g ≈ 9.81 m/s² (32.2 ft/s²) regardless of mass. A dropped ball gains 9.81 m/s of speed every second. On the Moon, g is only 1.62 m/s². See the free fall calculator for drop-height problems.