What is the Weight of mount Everest?

If we take a cone as a simplified shape of Everest, then we can use the following

formula to calculate its volume:

V = 1/3*pi*R^2*H

Here: http://www.the-aps.org/publications/tphys/legacy/1982/issue1/36.pdf - you can find a picture with the height and base of the Everest (from which we can get the radius):

H = 8848 m

R = 16093 m

then:

V = 2398.5 cubic km

mass is calculated from density of the rock and volume. Everest mainly consists of

limestone (~2.6 kg/cubic m) with layers of dolomite (~2.85 kg/cubic m).

Then

m = p*V = 2.7 (kg/cub. m)* 2398.5 (cub. km) = 6.5 *10^12 kg

If you want know the weight P, then

P = m*g - where the vector-g is the g-force.