Acceleration Calculator
Work out acceleration from a change in speed over time, or from the net force on a mass, and see it in m/s², g and ft/s².
From velocity change
a = (v − u) ÷ t
Solve for
a
Acceleration
m/s²
1 sig figs: 4
≡
Same value in
14.7 ft/s² · 448 cm/s²
- Rearrange: a = (v − u) ÷ t
- Substitute: u = 0 km/h, v = 100 km/h, t = 6.2 s (converted to SI units first).
- Result: a = 4.48029 m/s², rounded to 1 significant figures because the least precise input has 1.
From force and mass
a = F ÷ m
Solve for
a
Acceleration
m/s²
1 sig figs: 6
≡
Same value in
20.51 ft/s² · 625 cm/s²
- Rearrange: a = F ÷ m
- Substitute: F = 500 N, m = 80 kg (converted to SI units first).
- Result: a = 6.25 m/s², rounded to 1 significant figures because the least precise input has 1.
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Acceleration benchmarks
- Free fall on Earth: 9.81 m/s² (1 g)
- Family car 0–100 km/h in 10 s: 2.8 m/s² (0.28 g)
- Hard braking on dry road: about 8 m/s² (0.8 g)
- Space Shuttle launch, peak: about 29 m/s² (3 g), per NASA
For motion problems with displacement as well, use the kinematics calculator.
Frequently asked questions
What is the formula for acceleration?
a = (v − u) ÷ t: change in velocity divided by time. From forces, Newton’s second law gives a = F ÷ m. The SI unit is m/s².
Can acceleration be negative?
Yes. Negative acceleration means the velocity is changing in the negative direction. If the object moves in the positive direction, that is slowing down (deceleration).
What is 0–100 km/h acceleration in g?
A car doing 0–100 km/h in 6.2 s averages (27.8 m/s) ÷ 6.2 s = 4.48 m/s², which is 0.46 g. The result panel shows g-force for any answer.
Is an object moving in a circle at constant speed accelerating?
Yes. Its direction changes, so its velocity changes. The centripetal acceleration is v² ÷ r, pointing toward the centre.