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 toeboots (#064 , #067, #068, #1306, #1308, and #1309)tend to fit a bit bigger than other Blundstones because of the square toe box. For men subtract about 1.5 sizes, and for women subtract about 3 sizes.