How do I determine protein concentration for my western blot experiment?

Assays such as the Bradford assay, BCA assay, Lowry assay, and UV spectroscopy can be used to measure protein concentration for western blots. One should prepare a series of protein standards with known concentrations covering the expected range of  the samples. These standards will be used to generate a standard curve for quantification. After incubation, measure the absorbance of the standards and samples using the appropriate wavelength. Then plot the absorbance of the protein standards against their known concentrations to generate a standard curve. The protein concentration can roughly be calculated using the following formula: Concentration (mg/ml) = Absorbance at 280 nm / Path length (cm). Lastly, once the protein concentrations of the samples have been determined, calculate the final protein concentrations based on the dilution factors if there are any.