how many grams are 1 ml of PG or VG?
VG is about 1.04g /ml
PG is about 1.012 I think?
The Specific Gravity of USP VG is 1.26g per ml
The Specific Gravity Propylene Glycol is 1.008g per ml
These seem to be the values in the recipe calculator if I extracted them correctly.
Your figures are correct, glycol on mine is different by different sources
This is why Lars allowed for the ability to change the numbers.
The hard part is finding the numbers for what we use (individually). On top of which, you have to remember to change the numbers (in the calculator) every time you (or the vendor you buy from) change suppliers.
You can either accept the overall ‘generally accepted’ numbers (and not stress over the minutia), or settle for only buying from a reliable source that provides the necessary documentation to get the numbers from (and perhaps end up with an inferior quality of VG [for example], but have the numbers to satisfy your needs).