Try this reading the info at this link (scroll down about half way). It'll talk about the Harris-Benedict Formula and the one I think you want, the Katch-McArdle Formula. However, as it's been pointed out, the difference is minimal. For me it's the difference between a BMR of 1836 and 1879.
I find Berardi's calculator hard to believe. In the section labelled "exercise sessions". Is that PER DAY? If that's the case, I can see why the number is so high.
From the web site I linked: