[bandy]

Comparison shopping is difficult because the stores are allowed to get away with marking interchangeable items with wildly dissimilar units (type and/or magnitude), quoting per item, per ounce, per pound, per gram, per quart, etc., all on items that are sitting next to one another. All of the grocery chains that I've ever shopped at are guilty of this.

People who are serious about cooking know about the volumetric units used in cooking and the relationships between them. (teaspoons/3 = tablespoons)/16 = cups.

But your American friends who don't know how many ounces are in a pound? I hope you're kidding. That's basic stuff, taught in elementary (primary) school.

[maxxxxx]

I am not kidding. Most seem to be resigned to the fact that it’s 12 or 16 and that’s close enough. Also nobody knows how many cups are in a pack of flour so buying something for a recipe is hard too.

[mlok]

These comparisons are much easier in the metric system : it is either per unit or per kg. If it is per gram, it's easy still because *1000 or /1000 is very easy. (basically you just move the decimal point, no calculator needed)

It is because we count with base 10 numbers that metric is easy and imperial is difficult.

[henrikschroder]

Another related thing is the nutritional value info box that every food item in the US is required to have. That's a good thing in itself, except the US allows this info box to show the values "per serving", which is usually a completely arbitrary measurement, making it impossible to compare two food items to determine which has more sugar, or which has more protein.

In the EU, the same thing exists, but it is always per 100g or per 100ml. No exceptions. So comparing two food items is always super easy. I don't know why the US allows this idiotic loophole of per serving.

[llamathrowaway]

In UK it’s not uncommon to see price tags that say something like '50p per litre' (for bottled water) or '50p per 100 sheet' (for toilet paper).

You can see the prices per unit on their websites:

https://www.tesco.com/groceries/en-GB/search?query=bottled%2...

Not sure if this is required by regulations or it’s just the supermarkets being customer-friendly though.