Acceleration Calculator
Work out acceleration three ways: from a change in velocity over time, from distance and time, or from force and mass. Mix units freely and get the answer in m/s², ft/s² and g.
0 if starting from rest
How to use the Acceleration Calculator
- Choose the method that matches what you know.
- Enter the values and pick units for each.
- Press Calculate; results also update as you type.
- Read the acceleration in m/s², ft/s² and g.
- Check the chart and table to see velocity and distance over time.
Acceleration formulas
- From velocity and time: a = (v − v₀) / t
- From distance and time (constant acceleration): a = 2(d − v₀t) / t², or a = 2d / t² from rest
- From force and mass (Newton's second law): a = F / m
- Related: v = v₀ + at, d = v₀t + ½at², v² = v₀² + 2ad
Example: a car goes from 0 to 100 km/h in 8 s. 100 km/h = 27.78 m/s, so a = 27.78 / 8 = 3.47 m/s² (0.35 g), and it covers (0 + 27.78) / 2 × 8 = 111 m.
Typical accelerations
| Situation | Approx. acceleration | In g |
|---|---|---|
| Family car, 0–100 km/h in 10 s | 2.8 m/s² | 0.28 g |
| Sports car, 0–100 km/h in 3 s | 9.3 m/s² | 0.94 g |
| Free fall near Earth's surface | 9.81 m/s² | 1 g |
| Hard braking on dry road | about −8 m/s² | about −0.8 g |
| Free fall on the Moon | 1.62 m/s² | 0.17 g |
Unit conversions
1 m/s² = 3.2808 ft/s² = 3.6 km/h per second ≈ 2.237 mph per second ≈ 0.10197 g.
Frequently asked questions
What is the formula for acceleration?
Average acceleration is a = (v − v₀) / t: the change in velocity divided by the time taken. From Newton's second law it is also a = F / m, net force divided by mass.
What are the units of acceleration?
The SI unit is metres per second squared (m/s²): how many metres per second the velocity changes each second. Other units include ft/s² and g, where 1 g = 9.80665 m/s².
How do I find acceleration from distance and time?
For constant acceleration, d = v₀t + ½at², so a = 2(d − v₀t) / t². Starting from rest this becomes a = 2d / t². A sprinter covering 100 m in 10 s from rest averages 2 m/s² if acceleration were constant.
What is negative acceleration?
Negative acceleration means the velocity is decreasing in the chosen positive direction, often called deceleration. Braking from 60 mph (26.8 m/s) to 0 in 4 s is about −6.7 m/s².
How fast is a car that goes 0–100 km/h in 8 seconds accelerating?
100 km/h is 27.78 m/s, so a = 27.78 / 8 ≈ 3.47 m/s², about 0.35 g.
What is g-force?
g-force expresses acceleration as a multiple of standard gravity, 9.80665 m/s². An acceleration of 19.6 m/s² is 2 g.