Your weight is not the same thing as your mass. Instead your weight is derived by you mass times the gravitational forces of the earth. Refer to equation 1.

**(Eq 1)** $W=mg,~g=9.81/frac{m}{s^2}~or~32.2\frac{ft}{s^2}$

m = mass

g = gravitational constant

W = Weight

The gravitational constant g can change depending on the altitude you are at, or if you are on a different planet. Now there is a way to calculate the gravitational constant g. Basically you have to realize that every object is attracted to one another and gives off its on gravitational field. This means you are pulling on the earth just as much as the earth is pulling on you. However, your mass is so small compared to the earth’s mass; you basically have to no effect on the earth. To calculate the gravitational attraction between to particles equation 2 would be used.

**(Eq 2)** $f=G\frac{m_1m_2}{r^2},~G=66.73(10^{-12})\frac{m^3}{kgs^2}$

f = attraction force

G = Universal Gravitational Constant

m_{1} = mass of first object

m_{2} = mass of second object

r = distance between objects