SevenCubed - 9:27 pm on Oct 11, 2012 (gmt 0)
It would help if you pasted your html and css here so we can see it -- just the snippets that are involved, not all your code. Without seeing the code I can only think of margins and padding possibly being a factor but the difference of 200 pixels makes that seem unlikely. Also which browser? Have you tested it in various browsers? Have you validated your code? Have you explicitly defined the length and width in your css?