I calculate the bill as being a lot less.
According to my calculations, the bill comes to a lot less.
Try using this structure, it will please teachers , linguists, grammar puritans and examiners for an English Exam, and some job employers.
Although it is from an older way of speaking used as a negative comparison, it has become popular for some speakers to use "much less" where I have put "a lot less.
Much = great in importance or significance.
much = "obsolete" many in number.
Much = too much too many an excess an excessive amount.
"a lot" = same as much, if you read through the definitions.
Both from the same dictionary as the link provided by Tasneem
here is the definition for "much less"
Definition of much less
: not to mention —used especially in negative contexts to add to one item another denoting something less likely
He had trouble paying for a car, much less a high-definition TV.
And so it appears that he is never going to get out of the eighth grade, much less ever make it to college.
to use "less" in your sentences remove the "set comparator phrase" "much less" and say "a lot less".
do not say "far less" that also can mean other things and is also used as a comparator sometimes.
as in "far less likely"
It is also meaningless to say "much" + "less" when both words = the opposite.
And "a lot' the two word phrase is not the same as "lot" or a singular "a lot" = a piece of land or car park in American. UK we say "car park" and "a car lot for a place that sells cars, with cars parked on the lot.