If we're going to tackle the wild and woolly world of online shopping, first things first: what do all those different sizes mean?

Part of the beauty of online shopping is that we can get clothes and shoes from all over the world. But that's also part of the stress: what exactly do Australian sizes mean? What's an Italian 39? And is there a difference in Canada? There's a lot of information out there, much of it confusing. And even the following charts — while I hope they're clear — won't be a Rosetta Stone.

Then there's the question of Metric-Imperial conversion in blouses and bras. Here's a chart for that!

If you do better with words than numbers — I do — here's a very clear breakdown of how to calculate sizes, via the estimable eHow. I put all these to the test and found them roughly accurate.

If you wish to convert from American sizes to British clothing sizes, add 2 to the American or Canadian size. In the United States and Canada, a size 2 is equivalent to a British size 4, a 6 to an 8, 8 to 10 and so

When converting from American sizes to French sizes, you need to add 30 to the American/Canadian size. Thus, a 2 is equivalent to a 32, a 4 is a 34 in French sizing, 6 becomes 36 and so on.

For German sizing, you will need to add 28 to the American/Canadian size. Thus, an American 2 becomes a German 30, and a 14 is a 42.

Italian sizing is determined by adding 34 to the American/Canadian size. An American size 2 becomes an Italian size 36, a 4 becomes a 38, and so on.

Australian sizes are determined by adding the number 4 to the American size. A 2 becomes an Australian 6, and a 10 becomes a 14.

The Japanese conversion becomes an odd number. To get the correct Japanese size, you need to add the number 3 to the American/Canadian size. An American size 2 becomes a Japanese size 5, a 4 becomes a 7, and so on.