Acceleration Calculator

Acceleration is how fast velocity changes: \(a = \frac{v – v_{0}}{t}\). A car that goes from 0 to 100 km/h (27.78 m/s) in 5 s accelerates at 5.56 m/s², about 0.57 g.

How to use the acceleration calculator

1. Choose what you know: velocities and time, velocities and distance, or force and mass.
2. Enter the values and units; the calculator converts to SI units.
3. Press Calculate to get the acceleration in m/s², ft/s² and g.

Acceleration formulas

• \(a = \frac{v – v_{0}}{t}\) (definition, constant acceleration)
• \(a = \frac{v^{2} – v_{0}^{2}}{2d}\) (no time needed)
• \(a = \frac{F}{m}\) (Newton’s second law)

SI unit: meters per second squared (m/s²). Standard gravity is g = 9.80665 m/s².

Worked example

A plane reaches 70 m/s from rest over a 1,500 m runway: \(a = \frac{70^{2} – 0}{2 \times 1500} = 1.633\ \text{m/s}^{2}\), and the takeoff run takes \(t = \frac{70}{1.633} \approx 42.9\) s.

Signs and units

• Negative acceleration means the velocity is decreasing in the chosen positive direction (slowing down if moving forward).
• 1 km/h = 0.27778 m/s; 1 mph = 0.44704 m/s.
• Acceleration in g = a ÷ 9.80665.

Acceleration practice quiz: 10 questions

Test yourself with 10 multiple-choice questions. Choose an answer and press Submit to see if you are right and why. Your score appears at the end.

Frequently asked questions

How do you calculate acceleration?

Divide the change in velocity by the time it took: a = (v − v₀)/t. If you know the distance instead of the time, use a = (v² − v₀²)/(2d).

Can acceleration be negative?

Yes. Negative acceleration points opposite the positive direction; for an object moving forward, it means slowing down.

What is the unit of acceleration?

Meters per second squared (m/s²) in SI. Feet per second squared and g are also used.

How is acceleration related to force?

Newton’s second law: a = F/m, where F is the net force and m the mass.

What does 1 g mean?

An acceleration of 9.80665 m/s², equal to standard gravity at Earth’s surface.

Sources

• OpenStax University Physics Volume 1
• OpenStax College Physics 2e
• NIST Special Publication 811: Guide for the Use of the SI

Related calculators

• Force Calculator
• Speed Calculator
• Free Fall Calculator
• Projectile Motion Calculator
• Momentum and Impulse Calculator

Browse all calculators