actual size of an object

How do I find out the actual size of an object? It doesn’t seem to be in the scale.
I createt a primitive “plane” und a primitive “cube”. both have the x,z scale of 1,1 but the plane is much larger than the cube even soo it has the same scale. I want to resize the pplany by script, so it can carry a variable number of cubes.
How do i find out the actual size?

Yeah, good Idea - that’s how I did it. Thanks

Put a Box (or Sphere) Collider on the object. Then, see the XYZ size (or radius) of that in the Inspector, and assume it is meters.