Differentiate between measurement and estimation

Estimate is to calculate roughly, often from imperfect data while measure is to ascertain the quantity of a unit of material via calculated comparison with respect to a standard.

Measurement is a process in which we define the quantity of theproducts which exist, while estimating is a proccess of definingthe quantity of the imaginary things. such as we estimate for thecost of production of anything which will be completed (ready) laterbut we have immagined that it's cost will reach to this figure.