Average Acceleration Calculator
Average acceleration from two velocity readings and their times, or from a whole list of time–velocity readings with segment-by-segment results.
Average acceleration is the total change in velocity divided by the time it took. It is what you can measure with two speed readings and a stopwatch, and it is the figure physics problems usually ask for when the acceleration was not steady. Paste a column of readings from a data logger or video analysis and the calculator also shows the acceleration in each interval.
How to use this tool
- Choose two readings, or a list of readings.
- Pick the velocity unit your numbers use.
- For two readings, enter each velocity with the time it was taken. For a list, enter one "time, velocity" pair per line.
- Read the average acceleration in m/s² and g, plus the interval table for lists.
Formula
ā = Δv / Δt = (v₂ − v₁) / (t₂ − t₁)
v₁ and v₂ are the velocities at times t₁ and t₂. Velocity is converted to m/s before dividing, so the result is always in m/s². Only the end points matter for the average; the segment table divides each consecutive pair the same way.
Example
A car merging onto a motorway goes from 15 m/s at t = 2 s to 27 m/s at t = 8 s. Δv = 12 m/s and Δt = 6 s, so the average acceleration is 12 ÷ 6 = 2 m/s², about 0.204 g. With the sample sprint data (0 to 11.2 m/s over 5 s) the average is 2.24 m/s², but the table shows it falling from 3.2 m/s² in the first second to 1 m/s² in the last.
Frequently asked questions
How is average acceleration different from instantaneous acceleration?
Instantaneous acceleration is the rate of change at one moment (the slope of a velocity–time graph at a point). Average acceleration is the slope of the straight line joining the first and last points. Constant acceleration makes them equal everywhere; a varying acceleration may also equal its interval average at particular instants.
Can average acceleration be zero while the object is moving?
Yes. If an object starts and ends at the same velocity it has zero average acceleration, even if it sped up and slowed down in between, or moved at a steady speed the whole time.
What if the direction changes?
Enter velocities with a sign: positive one way, negative the other. A ball hitting a wall at +8 m/s and bouncing back at −6 m/s in 0.02 s has an average acceleration of (−6 − 8) ÷ 0.02 = −700 m/s².
Last updated: 2026-10-30