Protons are usually regarded by their mass, as mass is not specific to any gravitational acceleration. However, if you wished to find the weight of a proton on Earth, it would be:
Force (weight) = mass of proton * acceleration due to Earth's gravity
F = ma
F = (1.62 x 10^-27)(-9.8)
F = 1.5876 * 10^-26N
