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Vector Calculator (Dot Product, Cross Product, Angle)

Calculate the magnitude, dot product, cross product, and angle between two 2D or 3D vectors.

Magnitude of A
2.2361
Magnitude of B
2.2361
Dot product (A · B)
4
Cross product (A × B)
(0, 0, -3)
Magnitude of cross product
3
Angle between A and B
36.87°

How it works

Both vectors are treated as 3D — leave the z components at 0 to work with plain 2D vectors, since a 2D vector is just a 3D vector with no z component. Magnitude is |V| = √(x² + y² + z²), the direct extension of the Pythagorean theorem to three dimensions.

The dot product, A · B = x₁x₂ + y₁y₂ + z₁z₂, is a single number related to how aligned the two vectors are — it's used here (via A · B = |A||B|cos θ) to solve for the angle between them: θ = cos⁻¹((A · B) ÷ (|A||B|)).

The cross product, A × B = (y₁z₂ − z₁y₂, z₁x₂ − x₁z₂, x₁y₂ − y₁x₂), is a vector perpendicular to both A and B, with magnitude equal to the area of the parallelogram they span. When both inputs are 2D (z = 0), only its z component is nonzero — that single number is the standard '2D cross product', commonly used to test which way one vector turns relative to another.

FAQ

Why does the calculator reject the zero vector?

The angle formula divides by the product of the two magnitudes — if either vector is (0, 0, 0), its magnitude is 0, making that division undefined. Every other output (dot product, cross product) would still technically compute to 0, but there's no meaningful 'angle' between a vector and a point with no direction.

What does it mean if the cross product is the zero vector?

A cross product of (0, 0, 0) means the two vectors are parallel (or antiparallel) — there's no perpendicular direction to point in because they don't span a plane, only a line. You can check this directly: a 0° or 180° angle between A and B implies a zero cross product, and vice versa.

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