The comparison chart on my Burton box gives 26.5 for an 8.5 US sized boot, which is what I can jam my foot into in the Burton world. I don't have any other mondo measured gear.
That being said I just measured my foot from heel to toe and it's 25.5cm, so I don't know what to think. I'll see if I can go try on some other boots tomorrow, as I'm finally off work. Thanks!