3D Vector Calculator
Find magnitude and unit vector of a 3D vector
Result
How it is calculated
The magnitude is the length of the vector: |v| = √(x² + y² + z²), where x, y and z are the components along the three axes in the same unit (metres, newtons, any unit). The unit vector divides each component by that length: û = (x/|v|, y/|v|, z/|v|). The unit vector has length 1 and no unit of its own. Results are rounded to two decimals for display, so the rounded unit components may not square-sum to exactly 1. The zero vector (0, 0, 0) has no direction, so the tool returns no result for it. Negative components are fine and flip the sign of that component.
Worked example
Take v = (3, 4, 12). Squares: 9 + 16 + 144 = 169. Magnitude: √169 = 13.00. Unit vector: 3/13 = 0.23, 4/13 = 0.31, 12/13 = 0.92. So the direction of v is (0.23, 0.31, 0.92).
Common mistakes
- Entering a 2D vector and leaving z blank. All three components are required, so type 0 for z.
- Mixing units between components, for example x in metres and y in centimetres. The magnitude is meaningless unless all three share one unit.
- Expecting the unit vector to keep the original length. It always has length 1; only the direction is preserved.
- Trying to normalise (0, 0, 0). A zero vector has no direction, so there is no result.
About this calculator
From a vector's components (x, y, z), the calculator finds the magnitude with the 3D distance formula, |v| = √(x² + y² + z²), then divides each component by that magnitude to produce the unit vector — a vector of length 1 pointing in the exact same direction, the form most physics and graphics formulas require.
Physics students use it to resolve force, velocity, and displacement vectors in three dimensions, and game developers and 3D graphics programmers use unit vectors constantly for lighting normals, camera directions, and movement — anywhere a direction needs to be represented independently of its original length.
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