Two things: 1) math.floor returns a float, not an int. Doing an int() conversion on a float already floors the value, anyways. Try replacing math.floor(...) with int(...) e.g. >>> math.floor(5.9) 5.0 >>> int(5.9) 5 2) What kind of data is in f2m? If f2m is a float, you will get float values in the expressions that f2m is a multiplicand.