Acceleration Calculator
Calculate acceleration from a change in velocity over time.
About the Acceleration Calculator
Acceleration is how quickly velocity changes. A car going from 0 to 100 km/h (27.78 m/s) in 9.26 s accelerates at 3 m/s², about 0.31 g, where g = 9.80665 m/s² is standard gravity.
Enter the change in velocity and the time it took, or solve for either one. Slowing down gives a negative acceleration (deceleration), which is how braking performance is described.
The formula
a = Δv ÷ Δt
- a
- average acceleration, in m/s²
- Δv
- change in velocity (final minus initial), in m/s
- Δt
- time taken, in seconds (s)
Worked example
A car braking from 90 km/h to a stop in 4 s
- 90 km/h ÷ 3.6 = 25 m/s, so Δv = 0 − 25 = −25 m/s
- a = −25 ÷ 4 = −6.25 m/s²
- About 0.64 g of deceleration
Things to keep in mind
- Gives the average acceleration over the time; the rate may vary within it.
- Convert km/h to m/s by dividing by 3.6, and mph to m/s by multiplying by 0.44704.
Questions people ask
What is 1 g?
9.80665 m/s², the standard acceleration of gravity.
Can acceleration be negative?
Yes, deceleration is acceleration opposite to motion.