Among cutting-edge nanotechnologies, quantum-dot cellular automata (QCA) is a well-matched substitute for transistor-based technologies. Full-adder as a primary element of computational circuits has a great effect on other circuits. Hence this paper presents a new schematic design of QCA full-adder (QFA) to implement an efficient layout with minimum cells. The simple structure of the proposed design in minimum latency makes the aforementioned layout unique among state-of-the-art QFAs. Besides, different sizes of ripple carry adder (RCA) are implemented using this efficient full-adder layout to show its applicability. The proposed design of this work are simulated using QCADesigner tool. Moreover, The proposed full-adder have verified with physical formulas. 32.43% decreasing cell count and 50% increasing speed is the result of a comparison between our optimum QFA layout and previously published design with a similar structure. Ultimately different sizes of ripple carry adders of this paper are compared to the previous layouts and results show the performance of suggested RCA's structure.