Membraanimbumismõõturi üks kamber sisaldab puhast lahustit ja teine kamber lahust, milles lahustunud aine on tundmatu molekulmassiga polümeer, seejärel membraanimbumismõõturiga mõõdetakse läbi poolläbilaskva membraani lahusti imbumisrõhku, mille saadud mõõdist kasutatakse polümeeri proovi molekulmassi arvutamiseks.
One chamber of membrane osmometer contains pure solvent and the other chamber contains a solution in which the solute is a polymer with an unknown molecular mass. The osmotic pressure of the solvent across the semipermeable membrane is measured by the membrane osmometer, and this osmotic pressure measurement is used to calculate molecular mass for the sample.