If you are an American or Canadian, and you find a British recipe or a military
or commercial recipe that you want to try, you may find that the recipe gives
ingredient amounts by weight when what you are used to is volume measurements such
as cups and tablespoons. If you want to use a Europen recipe, you may find that it
is not only by weight, but is in metric units such as grams.
On the other hand, you may be European or British, and you may find yourself stymied
by American & Canadian recipes that are in cups and tablespoons.
The easiest, best solution for Americans and Canadians is to purchase a small
electronic kitchen scale that weighs in both ounces and in grams. This is easy and
not very costly. It takes no math or conversion tables, and you'll find having a
small scale is useful for other things as well.
For Brits and Europeans, the easiest solution is to purchase a two-cup measuring cup
and a set of measuring teaspoon/tablespoons. Neither of these is expensive, and like
the scale above, they require no math or conversion tables. Your local shop may not
have them, but you can easily get them over the Internet.
Why isn't there an easy conversion table? The answer is because Americans & Canadians
use volume measurements and Brits & Europeans use weight measurements,
and these two are not easily converted from one to the other. A given volume of one
substance often weighs more or less than an equal volume of another substance.
Substances have different densities. One cup (volume) of flour weighs 5.3
ounces or in metric 150.25 grams. On the other hand, One cup (volume) of sugar weighs
8 ounces, or in metric 226.8 grams. So, you can't just say that one cup (volume)
equals a given measurement in weight because it's different for different substances.
As if that weren't enough, in our system of weights and measures, we have two kinds
of "ounces". One is for volume: There are 8 fluid ounces in a cup and 16 fluid ounces
in a pint. The other is in weight: There are 16 ounces in a pound. Just remember that
if you measure it with a measuring cup, it's fluid onces (volume) and if you weigh it
on a scale, then it's ounces of weight.
For more on converting weights & measures, see here:
weight to volume & vice versa
metric to U.S. & vice versa