Counting words sounds like a simple task but it is not. In fact there are several different ways to do it — and that’s why different computer programs come up with different results for the task of counting words.
For example is “can’t” one word or two? How about “it’s” or “take-out”? Depending on what you decide to count as a word, you will get different word counts.
Word counts can easily vary by 10% depending on how how a ‘word’ is defined. So if your text is counted as 500 words in AutoCrit and 550 in Microsoft Word, don’t worry. Each word processing program is making internally consistent decisions about how to analyze your text.