Hi,
With shoes, there are several sizing systems used by different countries, and you have to make sure what market the shoes are made for.
http://www.aussiethings.com.au/articles.php?article=13
Even then you can't be absolutely confident online as they might even tell you a fib
I once bought a pair of shoes in a well known shoe store here, and noted they had a sign saying "guaranteed quality" or some such flim flam
I asked "what period are they guaranteed for in normal use?"......dodge, weave, "it depends", etc etc
"Well, if they fell apart after 2 weeks, would you replace them?"...."Oh yes"
"After 3 months?"......"Oh, um, ah, probably"
"After 6 months?"........"Oh no, not then"
"So all your shoes might only last 6 months?".......it was hilarious.
True though, you can wear out a pair of shoes in 6 months easily with hard wear.
Cheers