Proteins are involved in nearly every biological process, which makes them of interest to a range of scientists. Previous work has shown that hand-held cameras can be used to determine the concentration of colored analytes in solution, and this paper extends the approach to reactions involving a color change in order to quantify protein concentration (e.g., green to blue). Herein, we describe the successful use of smartphone colorimetry to quantify protein concentration using two common colorimetric biochemical methods, the Bradford and biuret assays. The ease of the experimental setup makes these lab experiments accessible to a wide range of students and can be used as both high school and college level laboratory experiments.