A well-known problem in the computer science area is related to numerical data representation, which directly affects adder circuits’ design and a reason to have different formats: IEEE Std. 754, Half-Unit-Biased (HUB), and Round-to-Nearest (RN). RN has an advantage that rounding to nearest is equivalent to a word truncation. It avoids double rounding errors and intermediate rounding steps with an exact conversion between formats, making it applicable to general problems. However, there is a lack of research on the hardware implementation of the RN representation. In this work, we propose hardware architectures for binary and floating-point adders, analyzing for the latter its performance in terms of error and resource consumption in FPGAs. To accomplish this, we have developed a one-bit RN-based adder that allows modular designs, considering an efficient signal propagation to obtain new architectures for both binary and floating-point single-precision adders. The results open new perspectives for further applications.