how many grams in an ounce?

I came across this article today: http://stuffstonerslike.com/2015/08/how-many-grams-in-an-ounce-of-weed/ I thought it was going to be some joke or something for newbs, but it actually points out that an ounce of weed isn't just 28 grams it's actually 28.349523125 grams. So every time I've...