The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology; such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method by a terminal, a method by a base station, a terminal, and a base station in a wireless communication system are provided. The method by the terminal includes receiving from a base station downlink control information including modulation and coding scheme (MCS) information; identifying a first transport block size based on the downlink control information; and identifying a second transport block size based on the first transport block size and a transport block size candidate set, wherein the transport block size candidate set includes elements having an interval of a multiple of 8.