Concerning the period of the Thermidorian Reaction we find Carlyle in his "A History" reporting the following:
This Convention, now grown Anti-Jacobin,did,with an eye to justify and fortify itself, publish Lists of what the Reign of Terror had perpetrated: Lists of Persons Guillotined. The Lists, cries splenetic Abbe Montgaillard, were not complete. They contain the names of, How many persons thinks the reader?—Two Thousand all but a few. There were above Four Thousand, cries Montgaillard: so many were guillotined... of whom Nine Hundred were women. (Montgaillard, iv. 241.) It is a horrible sum of human lives, M. l’Abbe:—some ten times as many shot rightly on a field of battle, and one might have had his Glorious-Victory with Te-Deum. It is not far from the two-hundredth part of what perished in the entire Seven Years War. By which Seven Years War, did not the great Fritz wrench Silesia from the great Theresa; and a Pompadour, stung by epigrams, satisfy herself that she could not be an Agnes Sorel? The head of man is a strange vacant sounding-shell, M. l’Abbe; and studies Cocker to small purpose.
A careful reading of the text indicates that Carlyle himself seems to scoff at the notion that less than two thousand (or even four thousand) were Guillotined. And from many other places in his book, it appears clear that there were far more victims of the guillotine. He mentions Forty Four thousand revolutionary committees all over France, collecting prisoners and sending them to Paris to be guillotined, as well as bands of Jacobins traversing all of France with portable guillotines that they would set up in the town square where they arrived, and haul in their victims to be beheaded - whole families at once, men women and children.
And we find a parade of "tumbrils" traversing the streets of Paris, carrying their victims to the guillotine, containing ten, twenty and as many as sixty at a time, for months on end or perhaps even a year.
The Revolutionaries also set up facilities for putting to use the human remains of their victims:
One other thing, or rather two other things, we will still mention; and no more: The Blond Perukes; the Tannery at Meudon. Great talk is of these Perruques blondes: O Reader, they are made from the Heads of Guillotined women! The locks of a Duchess, in this way, may come to cover the scalp of a Cordwainer: her blond German Frankism his black Gaelic poll, if it be bald. Or they may be worn affectionately, as relics; ren- dering one suspect? (Mercier, ii. 134.) Citizens use them, not without mockery; of a rather cannibal sort. Still deeper into one’s heart goes that Tannery at Meudon; not mentioned among the other miracles of tanning! ‘At Meudon,’ says Montgaillard with considerable calmness, ‘there was a Tannery of Human Skins; such of the Guillotined as seemed worth flaying: of which perfectly good wash-leather was made:’ for breeches, and other uses. The skin of the men, he remarks, was superior in toughness (consistance) and quality to shamoy;
This seems to indicate that there were far more than two thousand victims - these wigs and 'leather' products appear to have been fairly widespread, and it would hardly have been worth the trouble to set up such operations at all for only one thousand victims (one thousand men and one thousand women).
When I considered the number, it seemed to me that 100,000 would be a conservative estimate. If each of the 44,000 councils sent only one to the guillotine, we already have 44,000. Do we have a clear reckoning (not a simple count but an accounting) of how many heads were actually felled by guillotine during the Revolution?