Speedskating boot sizes are really confusing. In addition to the American shoe sizes, many speedskating boots are measured and/or manufactured on the European size scale, since speedskating is so popular in Europe. I have no idea how either American or European sizes work, but I take a size 10 American shoe, and am a European size 41. My feet are 27.5 cm long. If boots are made in European sizes, there are some American sizes that just don't match up, so boots might be available in American sizes 7, 7.5, 8, 9, 9.5 and 10, but not in American size 8.5 for example. In addition, the various boot manufacturers tend to size "differently". Bont thinks my American size 10 feet wear an American size 8 boot (i.e. Bont boots run big) and other manufacturers go the other way. To make matters worse, some companies just have their own random / arbitrary sizing scale.
To get around this confusion, you can usually send in a tracing of your feet to the company and they will tell you which size of theirs you wear. You can also for some manufacturers make plaster molds of your feet so they can recommend a size / style more exactly, or, you can custom order boots made specifically to fit your exact three-dimensional foot cast, for significantly more money of course.