Cross Product Calculator

Compute the cross product of two 3D vectors, plus the dot product, magnitudes and the angle between them.

How cross product is worked out

The cross product produces a vector perpendicular to both inputs, with a magnitude equal to the area of the parallelogram they span. It is the operation behind torque, angular momentum and surface normals in graphics.

The dot product is shown alongside because the two together characterise the relationship completely: the dot product measures how parallel the vectors are, the cross product how perpendicular.

How to fill it in

  1. Enter the three components of vector a.
  2. Enter the three components of vector b.
  3. Read the cross product, dot product and angle.

The maths behind it

a × b = (a₂b₃ − a₃b₂, a₃b₁ − a₁b₃, a₁b₂ − a₂b₁) a · b = a₁b₁ + a₂b₂ + a₃b₃ · cos θ = (a · b) ÷ (|a||b|)

A worked example

Take the starting scenario, a vector a of 3, vector b of 4. That gives a cross product a × b of (-15, -2, 39). Underneath, Dot product comes out at -13 and Angle between at 107.263°. Change any field and every figure updates as you type.

Common questions

What does the cross product mean geometrically?
It is perpendicular to both vectors, following the right-hand rule, with length equal to the area of the parallelogram they form.
When is the cross product zero?
When the vectors are parallel or antiparallel — there is no parallelogram, so the area is zero.
Does the cross product exist in 2D?
Not as a vector. In two dimensions you get a single scalar, which is the z-component of the 3D result.