Tested tool guide
Tested browser tools
Checked August 16, 2026
What Span & Subspace Visualizer does, with a checked example
The span of a set of vectors is everything you can reach by scaling and adding them, and this tool draws exactly that shape. Enter vectors in 2D or 3D and it renders the flat through the origin that holds every linear combination - a line, a plane, or the whole space - along with the dimension, a linear-independence verdict, and whether the vectors form a basis. The common surprise: adding vectors does not automatically grow the span. A third vector lying in the plane of the first two changes nothing; only a genuinely new direction adds a dimension.
Worked example
A concrete input and expected output from the current implementation.
Input
v1 = (1, 2) and v2 = (2, 4) in 2D
->
Expected output
Linearly dependent: v2 = 2v1. The span is the single line through the origin y = 2x, with dimension 1. The two vectors do not form a basis of the plane.
Every combination a(1,2) + b(2,4) equals (a + 2b)(1,2), so the span is all scalar multiples of (1,2) - the line y = 2x. Both vectors point along one direction, so they cover no more than a single vector would: the span has dimension 1, and since a basis of the plane needs two independent vectors, this set is not one.