Waist measurement... why am I so off!?

forkeeps251

OK, so I know my biggest area that I need to lose weight on is my waist. So rather than weighing all the time, I thought I would measure. I just did a quick measure at work by using my headphone cord and a ruler. I wrapped the cord around my waist at two different points... one around my largest area, which is around the area of my belly button, and one a little higher around a more narrow area, above my belly button, around where my elbows fall. I measured 43.5" around my belly button, and 39" in the higher area.

So, now I just went to look at the measurements of the jeans I have on right now (Gap). I'm wearing a size 12 right now, but I know Gap jeans are stretchy. I have a few size 14 items, and most of those are comfortable bordering on loose. So, even at my largest size, 14, the measurement charts say I have a 31.5" wasit, or a 30.5" if I go by the size 12. How am I so far off? I know no one can really tell me because they aren't here, but does it sound like I am doing something wrong? Has anyone else had this issue?

Ideally I would like to be a size 6 or 8, so do I need to lose 12" around my waist or 4.5"?