I haven't tested every possible combination of conversion but testing several shows that although the convertor displays results with decimals for non-integer results, any answer such as expected 0.0393 or even 0.1 shows as 0.
If the converter is to be fully useful, it should also supply conversions to/from Rankine
See Wikipedia temperature
Anybody working in Fahrenheit will need to use Rankine for gas pressure equations etc.
p.s. Since you do Energy conversions it would also be useful to do Power
p.p.s. In Length, you have a unit called inche. In English, this unit has no e i.e. it should be inch editHectare also has no trailing a
p.p.s. In Length, how about conversions for Nautical Mile, AU, parsec, Lightyear