Talk:War/@comment-26811107-20160320170236/@comment-27353238-20160326230324

To above, its not m = m1 - m2, it is technically Δm = m1 - m2, where m1 is the total initial mass, m2 is total mass final mass, so Δm is the mass that was either converted to energy or the energy converted to mass. As the particular amount of starting mass does not usually matter, only the difference in mass, which is the mass that was actually converted, actually matters. Thats why you see the equation as E = MC^2 normally, the first response was how you would actually have to calculate it as the only way to determine how much mass was converted is to subtract the start total mass from final total mass.