An integrated circuit may include a floating-point adder that supports variable precisions. The floating-point adder may receive first and second inputs to be added, where the first and second inputs each have a mantissa and an exponent. The mantissa and exponent values may be split into a near path and a far path using a dual path floating-point adder architecture depending on the difference of the exponents and on whether an addition or subtraction is being performed. The mantissa values may be left justified, while the sticky bits are right justified. The hardware for the largest mantissa can be used to support the calculations for the smaller mantissas using no additional arithmetic structures, with only some multiplexing and decoding logic.