Pretty simple converters. Has the original number in Original Number, to be compared to Re-decimalized. The main limiting factor is scratch floating-point-precision.
Thanks to @KlimbRio1 for sharing that the number of Hex digits can be found using ⌊log([Decimal number])/log(16)⌋+1 No idea what he was talking about regarding a binary search, though Thanks to @cs4912647 for the 0+((0x) Join ()) trick to convert Hex to Decimal