Binary‐code decimal (BCD) to Excess‐3 converters (BCD‐XS3) can be used as an interface between two systems with different codes, and they can be used to synchronize those systems. Two novel approaches for quantum dot cellular automata BCD‐XS3 are suggested, and the design parameters and the amount of energy dissipation are examined. The results have shown that design parameters in two designs of BCD‐XS3 have been optimized. The new designs of the BCD‐XS3 circuits are simulated, and the proposed design is examined in terms of complexity, latency, and total area. Design parameters have been optimized, showing the reduction in design parameters in the two proposed approaches, which are single layers. The first proposed design uses 119 cells with a delay of 1.5 clock cycles whose number of cells, complexity, and total area are improved by 16.78%, 25%, and 18.18%, respectively, compared with the best previous work. The second proposed design uses 81 cells with a delay of 1 clock. The number of cells, complexity, and total area are improved by 43.35%, 50%, and 50%, respectively, comparing the best previous work. Also, this study investigates the energy consumption in BCD‐XS3 for 0.5Ek, 1Ek, and 1.5Ek tunneling energy, which is improved by 31.00%, 33.01%, and 34.68%, respectively, for the first design and 42.59%, 48.74%, and 52.46% for the second design.