I've been using http://www.northernbrewer.com/refractometer-calculator/
for a while, but apparently it has a bug: when OG is 32 Brix, and FG is 17 Brix, it says that the gravity is 1.026, but then calculates the ABV to be 32.858. BeerSmith gives me 15.3, which I assume is more correct.
Can anyone explain? Or do I just avoid nb?