I've recently dropped to a UK size 14 i.e. a US size 10, on top. Sadly I'm still a UK 16/ US 12 on the bottom - I'm sure I'll be eternally pear-shaped. Anyway, my question is to do with waist size/general measurements. According to most things I've read online, the waist is above the belly button by at least an inch or two (i.e. the smallest part between your navel and rib cage.) With this in mind my waist measures at about 32 inches (with the tape stretched) and 33 1/2 (with the tape pulled, not too loose, but not stretched either.)
However, I recently read that the waist (for clothes) is in fact your navel/belly button, which measures 3-4 inches more than my "other" waist. So this has got me questioning a few things:
1) According to almost all size charts online a US 10 is 30-31 inch waist. Thus if I TRULY had a 37 inch waist (as the navel/belly-button idea indicates) then surely there's no way I would fit into a US 10 as comfortably as I do. I know clothes vary from shop to shop, and I do still have to buy 12s in some things, but for the most part I buy 10s and they are not tight at all. Can anyone confirm/deny the idea that the belly button area is the actual waist?
2) Does this apply to all clothes? Jeans, for example? Most clothes people wear are not very high waisted, so how does that work in terms of waist size? Since you'd think that clothes which fall lower (around belly button area) would use that area as the waist measurement.
3) When measuring the waist how tight should one pull the measuring tape - very tight? - or should it be kept loose to get an accurate measurement?
4) I’m never exactly sure where the smallest part of my waist is! The smallest part, technically, looks to be about 3 ½ inches or more above my belly button. If I look in a mirror, that is the bit that dips “inwards” more prominently than anywhere else, but does this sound too high to be the actual waist?
Sorry if these seem like weird questions, but I want to make sure I’m doing this accurately.


) when the chart says they measure at 28.5" in the waist. Which would make sense, if they actually fit at my natural waistline?