What is the r value for pink fiberglass insulators?

It varies with the thickness of the insulation

Generally, about R-3 per inch. 3 1/2" for a 2x4 stud cavity is R-11. 5 1/2" for a 2x6 stud cavity is R-19. But if there is any airflow it greatly reduces the insulating value. Also, the thermal bridging of wood structures reduces the performance of fiberglass insulation.