The sizes listed for Blundstones are UK sizes, and they fit bigger than their North American size counterpart.
The following is a rough guide for sizing yourself for a Blundstone:
For men, subtract about 1 full size from your North American size to find your Blundstone size. IE) US Size 11 is about a Size 10 in a Blundstone.
For women, subtract about 2.5 sizes from your North American size to find your Blundstone size. IE) US Size 8 is about a Size 5.5 in a Blundstone.
The children's sizes go up to size 3 UK. For a child, subtract 1 full size from their North American size. IE) US Size 2 is about a Size 1 in a Blundstone.
The chisel toe boots tend to fit a bit bigger than other Blundstones because of the square toe box. For women, subtract about 3 sizes, and for men subtract about 1.5 sizes for the chisel toe boots.
The women's series boots also tend to fit large. Subtract about 3 sizes for these boots.
Obviously this is only an estimate, as everybody's feet will fit a little differently.
Glebe Trotters carries every Blundstone style available in Canada, so if it is choice you want, you have come to the right place.