The degree of polymerization (DP) is the number of monomeric units in a macromolecule or polymer or oligomer molecule. It is a key characteristic of polymers that determines their physical properties. The degree of polymerization is calculated as the ratio of the molecular weight of a polymer to the molecular weight of the respective monomer unit. For a homopolymer, there is only one type of monomeric unit, and the average degree of polymerization is given by DP = Mn/M0, where Mn is the number-average molecular weight and M0 is the molecular weight of the monomer unit. The number-average degree of polymerization is a weighted mean of the degrees of polymerization of polymer species, weighted by the mole fractions (or the number of molecules) of the species. It is typically determined by measurements of the osmotic pressure of the polymer. The weight-average degree of polymerization is a weighted mean of the degrees of polymerization, weighted by the molecular weight of each species.

To calculate the degree of polymerization, you need to divide the molecular weight of the polymer by the molecular weight of the monomer unit. For example, if the molecular weight of tetrafluoroethylene is 120,000, its degree of polymerization is 120,000 / 100 = 1,200.