Go metric…. Dr. Lawrence is right.
But remember to measure the density of the sand (or anything you’re trying to measure by volume) Take a Xml measure and then weight it. Extrapolate the result. I work with weight, not volume because the density of the materials I use vary.
Metrics is based on water volume=weight 1 liter (1000ml) water = 1 kg. (roughly) 1kg of salt takes up less space than 1kg of water. It’s more dense. So, if I was to add 1 liter of salt to something, but what I meant to add was 1kg I would be messing up my batch. Oil, on the other hand, is lighter than water, so if I buy 1liter of oil, it’s not going to weigh 1kg. It’s usually somewhere around 900g. depending on the oil.
Of course, you’re going to be dealing with packing and that effects your volume. Your sand will be more packed on the bottom of what ever it is your’re filling, so you’re only going to be estimating this, to be sure.