Random calculations

Something i've been curious about. What would the energy yield of creating a planet via Mass Energy be?

Well let's use a tiny planet.

Mercury has a radius of 2,440 km.

(4 × pi × 2,440^3)/3 = 60,849,650,526.2 km^3, or 6.0849650526199996e+19 m^3

Mercury has a density of 13,690 kg/m^3...which is nearly 3 times the density of Earth. Huh, neat.

13,690 * 6.0849650526199996e+19 = 8.3303172e+23 kg

E=MC^2

E = Energy in J

M = Mass in kg

C = speed of light in m/s

8.3303172e+23 * 299,800,000^2 = 7.4872924e+40 J

Approx 0.0007 FOE. Not bad.