there is no edit feature on posts, huh? I take this back, you can say "How many percentages?", but it does not mean the same thing as "How many percents?". To be equal to "How many percents", you can say "How many percentage points?"

You can say, "20 percent", but not "20 percentage" You can say, "what's the percentage?", but not "What's the percent"" You can say, "How many percents?", but not "How many percentages?" "Percentage" is the collect noun, whereas "percent" is used more like the unit.

Syutbai explained it well. However another better understanding of it is that 'percentages' is used in mathematical situations, though it still has the same rule or rather meaning of 'per hundred'. Percent can be identified as being one part in a hundred. and more or less i suppose it used in the business industry and mathematical terms as well. such as "The employment rate increased to 1 percent this year." Overall both words are exactly the same. You can use either of them in a sentence depending on what your sentence is.

percentage - the number, amount, rate of something, expressed as if it is part of total which is 100; a part or share of a whole. percent - one part in every hundred.