Calculate the magnitude of acceleration three ways: from mass and net force, from acceleration components (x, y, z), or from velocity vectors and time. Enter your known values and get the acceleration magnitude in m/s² along with supporting results for each method. Also try the Acceleration Calculator.
Magnitude of Acceleration
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Change in Speed |Δv|
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Formula Applied
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Net Force (F = ma)
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Acceleration is the rate of change of velocity with respect to time. Since velocity is a vector quantity (it has both magnitude and direction), acceleration is also a vector. The SI unit of acceleration is meters per second squared (m/s²). When we talk about the 'magnitude' of acceleration, we mean only the size of that vector — ignoring direction. See also our Free Fall with Air Resistance Calculator.
Newton's second law gives us F = m·a, which rearranges to a = F/m. The magnitude of acceleration equals the magnitude of the net force divided by the object's mass. For example, a net force of 50 N applied to a 10 kg object produces an acceleration magnitude of 5 m/s².
If you know the individual x, y, and z components of the acceleration vector, the magnitude is found using the Pythagorean theorem: |a| = √(ax² + ay² + az²). For a 2D problem with ax = 3 m/s² and ay = 4 m/s², the magnitude is √(9 + 16) = 5 m/s².
First, compute the change in velocity vector by subtracting the initial velocity vector from the final velocity vector component by component (Δvx = v2x − v1x, etc.). Then find the magnitude of that difference vector using |Δv| = √(Δvx² + Δvy² + Δvz²). Finally, divide by the time interval: |a| = |Δv| / t. You might also find our Stopping Distance Calculator useful.
Using a = F/m, the magnitude of acceleration is 50 N ÷ 100 kg = 0.5 m/s². This is a direct application of Newton's second law where the net force is divided by the object's mass.
Acceleration is a vector quantity — it has both magnitude and direction. The 'magnitude of acceleration' (also called the scalar acceleration or speed of acceleration) is the vector's length, which is always a non-negative number. Two objects can have the same acceleration magnitude but different directions of acceleration.
Speed is a scalar (magnitude only), while velocity is a vector (magnitude and direction). Because acceleration depends on the change in the full velocity vector, an object can be accelerating even if its speed stays constant — for example, a car turning at a fixed speed still has a changing velocity direction, and therefore a non-zero acceleration.
The SI unit is meters per second squared (m/s²). Other units include cm/s², ft/s², and the 'g-force' unit where 1 g ≈ 9.81 m/s². In this calculator all inputs and outputs use SI units (m/s², kg, N, m/s, s) to stay consistent with standard physics conventions.