are american shoes the same as british shoe sizes?

Dear Mk 46

No, they are not. You can see a shoe-size converting table here, to
know what's your British shoe size in "American" is, and vice versa:

Shoe Size Converter
<http://onlineconverters.com/shoes.html> 

Veganline - Shoe sizes 
<http://www.veganline.com/shoe-sizes.htm> - in a chart form

Apparel Size Guides 
<http://www.overstock.com/sizing.html> - another detailed chart

Wikipedia 
<http://en.wikipedia.org/wiki/Shoe_size> - a long explanation on the
different systems to determine shoe sizes, with a chart, too.

I hope this answers your question. Please contact me if you need any
clarification on this answer before you rate it.