Case 1
- Initial velocity (vi)
- 0m/s
- Final velocity (vf)
- 27.78m/s
- Time elapsed (t)
- 10s
2.778m/s²
Open with these valuesAverage Acceleration Calculator
2.778m/s²
Result: 2.778 m/s²Average acceleration is the change in velocity divided by the time it took: going from 0 to 27.78 m/s in 10 s gives 2.778 m/s². A negative answer means the object slowed down. Enter metres per second and seconds, and the result comes out in metres per second squared.
Worked examples
Case 2
- Initial velocity (vi)
- 50m/s
- Final velocity (vf)
- 0m/s
- Time elapsed (t)
- 10s
-5.000m/s²
Open with these valuesCase 3
- Initial velocity (vi)
- 10m/s
- Final velocity (vf)
- 30m/s
- Time elapsed (t)
- 4s
5.000m/s²
Open with these valuesHow it's calculated
a = (vf − vi) ÷ t
- StepEnter the velocity at the start of the interval, in metres per second.
- StepEnter the velocity at the end, and how many seconds the change took.
- ResultRead the average acceleration; a negative value means it slowed down.
Reference table
| vi, vf, t | What it describes | Acceleration (m/s²) |
|---|---|---|
| 0, 27.78, 10 | Car from rest to 100 km/h in 10 s | 2.778 |
| 0, 100, 5 | A very hard launch | 20 |
| 10, 30, 4 | Merging onto a motorway | 5 |
| 20, 20, 2 | Steady speed, nothing changes | 0 |
| 50, 0, 10 | Braking to a standstill | -5 |
Questions
What is average acceleration?
It is the change in velocity divided by the time over which it happens: a = (vf − vi) ÷ t. It tells you how quickly an object sped up or slowed down across an interval, on average. A car going from 0 to 27.78 m/s in 10 s averages 2.778 m/s².
What does a negative acceleration mean?
A negative result means the object slowed down over the interval — its final velocity was lower than its initial one. Slowing from 50 m/s to 0 m/s in 10 s gives (0 − 50) ÷ 10 = −5 m/s². The sign simply shows the direction of the velocity change.
What units does acceleration use?
The SI unit is the metre per second squared (m/s²) — one metre per second of velocity gained for every second that passes. Enter both velocities in m/s and the time in seconds, and no conversion is needed. To turn 27.78 m/s into km/h, multiply by 3.6.
Is this the same as instantaneous acceleration?
No, this is the average over the whole interval — the single rate that would produce the same velocity change in the same time. The actual acceleration can vary from moment to moment: a car may push harder at first and ease off later, yet still average 2.778 m/s².
Sources and last check
Information, not professional advice.