The groundwork for the calculation was performed in the 1980’s by Professor W.H. Press and colleagues. But now Professor Don Page from the Department of Physics at the University of Alberta has recomputed the estimate … using the Bohr radius multiplied by the three-tenths power of the ratio of the electrical to gravitational forces between two protons. The professor explains -

“My new estimate gives a height of about 3.6 meters rather than Press’s original estimate of about 2.6 cm.“

His paper ‘The Height of a Giraffe’ was published in the journal Foundations of Physics, Volume 39, Number 10/October, 2009. A full copy is available here