I am finding conflicting information when searching online for 1) The size of Napoleon's army when he invaded Russia and 2) The number of casualties in the Battle of Borodino. There are many books on this topic, but not in my library. I would really appreciate if someone could suggest a reliable source and would be delighted if they could mention page numbers.
A good summary is provided by Minard's chart of 1869; see Analyzing Minard's Visualization Of Napoleon's 1812 March for an analysis.
If you click on the graphic you find 422,000 is the starting size, but this is in Lithuania. It is 400,000 at Vilnius, but 60,000 troops are removed on the upper branch.